Tải giáo án điện tử dạy thêm Toán 8 KNTT Bài 28: Hàm số bậc nhất và đồ thị của hàm số bậc nhất

<p><strong><span data-contrast="none">CH&Agrave;O MỪNG C&Aacute;C EM </span></strong><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:2,&quot;335551620&quot;:2,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:0,&quot;335559740&quot;:360}">&nbsp;</span></p>

<p><strong><span data-contrast="none">ĐẾN VỚI B&Agrave;I GIẢNG H&Ocirc;M NAY</span></strong><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:2,&quot;335551620&quot;:2,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:0,&quot;335559740&quot;:360}">&nbsp;</span></p>

<p><strong><span data-contrast="none">B&agrave;i 28:&nbsp; H&Agrave;M SỐ BẬC NHẤT V&Agrave; ĐỒ THỊ H&Agrave;M SỐ BẬC NHẤT</span></strong><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:2,&quot;335551620&quot;:2,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:0,&quot;335559740&quot;:360}">&nbsp;</span></p>

<p><strong><span data-contrast="none">PHIẾU B&Agrave;I TẬP SỐ 1</span></strong><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:2,&quot;335551620&quot;:2,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:0,&quot;335559740&quot;:360}">&nbsp;</span></p>

<p><strong><span data-contrast="none">DẠNG 1: X&Aacute;C ĐỊNH H&Agrave;M SỐ L&Agrave; H&Agrave;M SỐ BẬC NHẤT</span></strong><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:2,&quot;335551620&quot;:2,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:0,&quot;335559740&quot;:360}">&nbsp;</span></p>

<p><strong><span data-contrast="none">B&agrave;i 1. </span></strong><span data-contrast="none">Trong c&aacute;c h&agrave;m số sau, h&agrave;m số n&agrave;o l&agrave; h&agrave;m sổ bậc nhất? H&atilde;y x&aacute;c định c&aacute;c hệ số a, b v&agrave; x&eacute;t xem h&agrave;m số n&agrave;o đồng biến?</span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:6,&quot;335551620&quot;:6,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:360}">&nbsp;</span></p>

<ol>

<li><span data-contrast="none">a) y = -2x &ndash; 3</span></li>

</ol>

<p><span data-contrast="none">H&agrave;m số y = -2x &ndash; 3 l&agrave; h&agrave;m số bậc nhất, trong đ&oacute; a = -2; b = -3 &nbsp;</span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:2,&quot;335551620&quot;:2,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:0,&quot;335559740&quot;:360}">&nbsp;</span></p>

<ol>

<li><span data-contrast="none">b) y = </span><span data-contrast="auto">-3/4</span><span data-contrast="none">x</span></li>

</ol>

<p><span data-ccp-props="{}">&nbsp;</span></p>

<p><span data-contrast="none">L&agrave; h&agrave;m số bậc nhất với a = </span><span data-contrast="none">-3/4</span><span data-contrast="none"> ; b = 0</span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:1,&quot;335551620&quot;:1,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:0,&quot;335559740&quot;:360}">&nbsp;</span></p>

<ol>

<li><span data-contrast="none">c) y = -3x</span><span data-contrast="none"><span data-fontsize="40">2</span></span><span data-contrast="none"> + 5</span></li>

</ol>

<p><span data-contrast="none">H&agrave;m số y = -3x</span><span data-contrast="none"><span data-fontsize="40">2</span></span><span data-contrast="none"> + 5 kh&ocirc;ng phải l&agrave; h&agrave;m số bậc nhất.</span> <span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:1,&quot;335551620&quot;:1,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:0,&quot;335559740&quot;:360}">&nbsp;</span></p>

<ol>

<li><span data-contrast="none">d) y = </span><span data-contrast="auto">&radic;3</span><span data-contrast="none"> . (x &ndash; 1) + </span><span data-contrast="auto">&radic;2</span></li>

</ol>

<p><span data-contrast="none">H&agrave;m số y = </span><span data-contrast="none">&radic;3</span><span data-contrast="none"> . (x &ndash; 1) + </span><span data-contrast="none">&radic;2&nbsp; </span><span data-contrast="none">= </span><span data-contrast="none">&radic;3</span><span data-contrast="none">x - </span><span data-contrast="none">&radic;3</span><span data-contrast="none"> + </span><span data-contrast="none">&radic;2</span><span data-contrast="none"> l&agrave; h&agrave;m số bậc nhất, trong đ&oacute;: a = </span><span data-contrast="none">&radic;3</span><span data-contrast="none">; b = </span><span data-contrast="none">-&radic;3</span><span data-contrast="none"> + </span><span data-contrast="none">&radic;2</span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:1,&quot;335551620&quot;:1,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:0,&quot;335559740&quot;:360}">&nbsp;</span></p>

<p><strong><span data-contrast="none">B&agrave;i 2</span></strong><span data-contrast="none">. </span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:6,&quot;335551620&quot;:6,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:360}">&nbsp;</span></p>

<ol start="6">

<li><span data-contrast="none">a) Cho h&agrave;m số y = ax + 6. T&igrave;m hệ số a của h&agrave;m số, biết rằng:</span></li>

</ol>

<p><span data-contrast="none">Khi x = -1 th&igrave; y = 5</span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:1,&quot;335551620&quot;:1,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:0,&quot;335559740&quot;:360}">&nbsp;</span></p>

<p><span data-contrast="none">Cho h&agrave;m số y = ax + 6</span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:6,&quot;335551620&quot;:6,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:360}">&nbsp;</span></p>

<p><span data-contrast="none">Khi x = -1 th&igrave; y = 5, thay v&agrave;o h&agrave;m số ta c&oacute;: </span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:6,&quot;335551620&quot;:6,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:360}">&nbsp;</span></p>

<p><span data-contrast="none">5 = a.(-1) + 6 suy ra a = 1</span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:6,&quot;335551620&quot;:6,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:360}">&nbsp;</span></p>

<ol>

<li><span data-contrast="none">b) Cho h&agrave;m số y = ax + b. T&igrave;m hệ số a v&agrave; b của h&agrave;m số, biết rằng:</span></li>

</ol>

<p><span data-contrast="none">Khi x = -1 th&igrave; y = -1 v&agrave; khi x = 0 th&igrave; y = -2</span><span data-ccp-props="{}">&nbsp;</span></p>

<p><span data-contrast="none">Cho h&agrave;m số y = ax + b</span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:6,&quot;335551620&quot;:6,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:360}">&nbsp;</span></p>

<p><span data-contrast="none">Khi x = -1 th&igrave; y = 1 thay v&agrave;o h&agrave;m số ta c&oacute;: 1 = a. (-1) + b </span><span data-contrast="none">&rarr;</span><span data-contrast="none"> b = a + 1</span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:6,&quot;335551620&quot;:6,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:360}">&nbsp;</span></p>

<p><span data-contrast="none">Khi x = 0 th&igrave; y = -2 thay v&agrave;o h&agrave;m số ta c&oacute;: -2 = a. 0 + b </span><span data-contrast="none">&rarr;</span><span data-contrast="none"> b = -2</span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:6,&quot;335551620&quot;:6,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:360}">&nbsp;</span></p>

<p><span data-contrast="none">Suy ra a + 1 = -2 </span><span data-contrast="none">&rarr;</span><span data-contrast="none"> a = -3</span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:6,&quot;335551620&quot;:6,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:360}">&nbsp;</span></p>

<p><span data-contrast="none">Vậy h&agrave;m số l&agrave;: y = -3x &ndash; 2</span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:6,&quot;335551620&quot;:6,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:360}">&nbsp;</span></p>

<p><strong><span data-contrast="none">B&agrave;i 3. </span></strong><span data-contrast="none">Với gi&aacute; trị n&agrave;o của m th&igrave; h&agrave;m số sau l&agrave; h&agrave;m số bậc nhất</span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:6,&quot;335551620&quot;:6,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:360}">&nbsp;</span></p>

<ol>

<li><span data-contrast="none">a) y = x</span><span data-contrast="auto">&radic;(m+3)</span><span data-contrast="none"> + </span><span data-contrast="auto">1/2</span></li>

</ol>

<p><span data-contrast="none">H&agrave;m số y = x</span> <span data-contrast="none">&radic;(m+3)</span><span data-contrast="none"> + </span><span data-contrast="none">1/2</span><span data-contrast="none"> l&agrave; h&agrave;m số bậc nhất khi:</span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:1,&quot;335551620&quot;:1,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:360}">&nbsp;</span></p>

<p><span data-contrast="none">&radic;(m+3)</span> <span data-contrast="none">&ne;</span><span data-contrast="none"> 0 </span><span data-contrast="none">&hArr;</span><span data-contrast="none"> m + 3 &gt; 0 </span><span data-contrast="none">&hArr;</span><span data-contrast="none"> m &gt; -3</span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:2,&quot;335551620&quot;:2,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:360}">&nbsp;</span></p>

<p><span data-contrast="none">Vậy khi m &gt; -3 th&igrave; h&agrave;m số l&agrave; h&agrave;m số bậc nhất</span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:1,&quot;335551620&quot;:1,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:360}">&nbsp;</span></p>

<ol>

<li><span data-contrast="none">b) y = x</span><span data-contrast="auto">&radic;(m^2-4m+4)</span><span data-contrast="none"> - 3</span></li>

</ol>

<p><span data-contrast="none">y = x</span> <span data-contrast="none">&radic;(m^2-4m+4)</span><span data-contrast="none"> - 3 </span> <span data-contrast="none">= x</span> <span data-contrast="none">&radic;((m-2)^2 )</span><span data-contrast="none"> - 3</span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:6,&quot;335551620&quot;:6,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:360}">&nbsp;</span></p>

<p><span data-contrast="none">= x. |m &ndash; 2| - 3</span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:6,&quot;335551620&quot;:6,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:360}">&nbsp;</span></p>

<p><span data-contrast="none">Ta c&oacute;: |m &ndash; 2| &gt; 0 với </span><span data-contrast="none">&forall;</span><span data-contrast="none">m </span><span data-contrast="none">&ne;</span><span data-contrast="none"> 2</span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:6,&quot;335551620&quot;:6,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:360}">&nbsp;</span></p>

<p><span data-contrast="none">Vậy khi m </span><span data-contrast="none">&ne;</span><span data-contrast="none"> 2 th&igrave; h&agrave;m số l&agrave; h&agrave;m số bậc nhất.</span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:6,&quot;335551620&quot;:6,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:360}">&nbsp;</span></p>

<ol>

<li><span data-contrast="none">c) y = </span><span data-contrast="auto">(-2/(m^2-1))</span><span data-contrast="none">x + </span><span data-contrast="auto">9/2</span></li>

</ol>

<p><span data-contrast="none">y = </span><span data-contrast="none">(-2/(m^2-1))</span><span data-contrast="none">x + </span><span data-contrast="none">9/2</span><span data-contrast="none"> l&agrave; h&agrave;m số bậc nhất khi:</span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:6,&quot;335551620&quot;:6,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:360}">&nbsp;</span></p>

<p><span data-contrast="none">-2/(m^2-1)</span> <span data-contrast="none">&ne;</span><span data-contrast="none"> 0 </span><span data-contrast="none">&hArr;</span><span data-contrast="none"> m</span><span data-contrast="none"><span data-fontsize="40">2</span></span><span data-contrast="none"> &ndash; 1 </span><span data-contrast="none">&ne;</span><span data-contrast="none"> 0 </span><span data-contrast="none">&hArr;</span><span data-contrast="none"> m </span><span data-contrast="none">&ne;</span> <span data-contrast="none">&plusmn;</span><span data-contrast="none">1</span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:6,&quot;335551620&quot;:6,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:360}">&nbsp;</span></p>

<p><span data-contrast="none">Vậy với m </span><span data-contrast="none">&ne;</span> <span data-contrast="none">&plusmn;</span><span data-contrast="none">1 th&igrave; h&agrave;m số l&agrave; h&agrave;m số bậc nhất.</span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:6,&quot;335551620&quot;:6,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:360}">&nbsp;</span></p>

<ol>

<li><span data-contrast="none">a) T&iacute;nh gi&aacute; trị của y khi x = 3 + 2</span><span data-contrast="auto">&radic;2</span></li>

</ol>

<p><span data-contrast="none">Khi x = 3 + 2</span><span data-contrast="none">&radic;2</span><span data-contrast="none"> thay v&agrave;o h&agrave;m số, ta c&oacute;:</span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:6,&quot;335551620&quot;:6,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:360}">&nbsp;</span></p>

<p><span data-contrast="none">y = (3 - 2</span><span data-contrast="none">&radic;2</span><span data-contrast="none">)(3 + 2</span><span data-contrast="none">&radic;2</span><span data-contrast="none">) &ndash; 1 = 9 &ndash; 8 + </span><span data-contrast="none">&radic;2</span><span data-contrast="none"> - 1 = </span><span data-contrast="none">&radic;2</span> <span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:6,&quot;335551620&quot;:6,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:360}">&nbsp;</span></p>

<ol>

<li><span data-contrast="none">b) T&igrave;m c&aacute;c gi&aacute; trị của x để y = 0</span></li>

</ol>

<p><span data-contrast="none">Để y = 0 </span><span data-contrast="none">&hArr;</span><span data-contrast="none"> (3 - 2</span><span data-contrast="none">&radic;2</span><span data-contrast="none">)x + </span><span data-contrast="none">&radic;2</span><span data-contrast="none"> - 1 = 0 </span><span data-contrast="none">&hArr;</span><span data-contrast="none"> x = </span><span data-contrast="none">(1-&radic;2)/(3-2&radic;2)</span><span data-contrast="none"> = </span><span data-contrast="none">-&radic;2</span><span data-contrast="none"> - 1</span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:1,&quot;335551620&quot;:1,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:0,&quot;335559740&quot;:360}">&nbsp;</span></p>

<p><strong><span data-contrast="none">PHIẾU B&Agrave;I TẬP SỐ 2</span></strong><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:2,&quot;335551620&quot;:2,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:0,&quot;335559740&quot;:360}">&nbsp;</span></p>

<p><strong><span data-contrast="none">DẠNG 2: ĐỒ THỊ H&Agrave;M SỐ y = ax</span></strong><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:2,&quot;335551620&quot;:2,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:0,&quot;335559740&quot;:360}">&nbsp;</span></p>

<p><strong><span data-contrast="none">B&agrave;i 1. </span></strong><span data-contrast="none">Cho h&agrave;m số y = </span><span data-contrast="auto">-5/2</span><span data-contrast="none">x </span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:1,&quot;335551620&quot;:1,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:0,&quot;335559740&quot;:360}">&nbsp;</span></p>

<ol>

<li><span data-contrast="none">a) X&aacute;c định vị tr&iacute; điểm A (1; </span><span data-contrast="auto">-5/2</span><span data-contrast="none">) tr&ecirc;n mặt phẳng toạ độ, v&agrave; vẽ đồ thị h&agrave;m số</span></li>

<li><span data-contrast="none">b) X&eacute;t xem trong c&aacute;c điểm sau, điểm n&agrave;o thuộc đồ thị h&agrave;m số?</span></li>

</ol>

<p><span data-contrast="none">B(2; -5); C(3; 7); D(1; </span><span data-contrast="auto">5/2</span><span data-contrast="none">); E (0; 4)</span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:1,&quot;335551620&quot;:1,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:0,&quot;335559740&quot;:360}">&nbsp;</span></p>

<p><span data-contrast="none">Thay toạ độ từng điểm đ&atilde; cho v&agrave;o phương tr&igrave;nh y = </span><span data-contrast="none">-5/2</span><span data-contrast="none">x ta được:</span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:1,&quot;335551620&quot;:1,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:0,&quot;335559740&quot;:360}">&nbsp;</span></p>

<p><span data-contrast="none">(x</span><span data-contrast="none"><span data-fontsize="40">B</span></span><span data-contrast="none">) = </span><span data-contrast="none">-5/2</span><span data-contrast="none">x</span><span data-contrast="none"><span data-fontsize="40">B </span></span><span data-contrast="none">= </span><span data-contrast="none">-5/2</span><span data-contrast="none"> . 2 = -5 = y</span><span data-contrast="none"><span data-fontsize="40">B</span></span><span data-contrast="none"> ; f(x</span><span data-contrast="none"><span data-fontsize="40">C</span></span><span data-contrast="none">) = </span><span data-contrast="none">-5/2</span><span data-contrast="none">x</span><span data-contrast="none"><span data-fontsize="40">C</span></span><span data-contrast="none"> = </span><span data-contrast="none">-5/2</span><span data-contrast="none"> . 3 = </span><span data-contrast="none">-15/2</span> <span data-contrast="none">&ne;</span><span data-contrast="none"> y</span><span data-contrast="none"><span data-fontsize="40">C</span></span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:1,&quot;335551620&quot;:1,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:0,&quot;335559740&quot;:360}">&nbsp;</span></p>

<p><span data-contrast="none">f(x</span><span data-contrast="none"><span data-fontsize="40">D</span></span><span data-contrast="none">) = </span><span data-contrast="none">-5/2</span><span data-contrast="none">x</span><span data-contrast="none"><span data-fontsize="40">D</span></span><span data-contrast="none"> = </span><span data-contrast="none">-5/2</span><span data-contrast="none"> . (-1) = </span><span data-contrast="none">5/2</span><span data-contrast="none"> ; f(x</span><span data-contrast="none"><span data-fontsize="40">E</span></span><span data-contrast="none">) = </span><span data-contrast="none">-5/2</span><span data-contrast="none">x</span><span data-contrast="none"><span data-fontsize="40">E</span></span><span data-contrast="none"> = </span><span data-contrast="none">-5/2</span><span data-contrast="none"> . 0 = 0 </span><span data-contrast="none">&ne;</span><span data-contrast="none"> y</span><span data-contrast="none"><span data-fontsize="40">E</span></span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:1,&quot;335551620&quot;:1,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:0,&quot;335559740&quot;:360}">&nbsp;</span></p>

<p><span data-contrast="none">Suy ra c&aacute;c điểm B, D thuộc đồ thị h&agrave;m số y = </span><span data-contrast="none">-5/2</span><span data-contrast="none">x, điểm C, E kh&ocirc;ng thuộc đồ thị h&agrave;m số.</span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:6,&quot;335551620&quot;:6,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:360}">&nbsp;</span></p>

<p><strong><span data-contrast="none">B&agrave;i 2. </span></strong><span data-contrast="none">Cho h&agrave;m số y = 3x</span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:6,&quot;335551620&quot;:6,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:360}">&nbsp;</span></p>

<p><span data-contrast="none">Vẽ đồ thị h&agrave;m số</span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:6,&quot;335551620&quot;:6,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:360}">&nbsp;</span></p>

<p><span data-contrast="none">Cho x = 1 </span><span data-contrast="auto">&rarr;</span><span data-contrast="none"> y = 3 </span><span data-contrast="auto">&rarr;</span><span data-contrast="none"> đồ thị h&agrave;m số đi qua M(1;3)</span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:6,&quot;335551620&quot;:6,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:360}">&nbsp;</span></p>

<p><span data-contrast="none">Cho x = 0 </span><span data-contrast="auto">&rarr;</span><span data-contrast="none"> y = 0 </span><span data-contrast="auto">&rarr;</span><span data-contrast="none"> đồ thị h&agrave;m số đi qua O(0;0)</span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:6,&quot;335551620&quot;:6,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:360}">&nbsp;</span></p>

<p><strong><span data-contrast="none">B&agrave;i 3. </span></strong><span data-contrast="none">Cho c&aacute;c h&agrave;m số y = -2x v&agrave; y = x </span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:6,&quot;335551620&quot;:6,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:360}">&nbsp;</span></p>

<ol>

<li><span data-contrast="none">a) Vẽ tr&ecirc;n c&ugrave;ng một hệ trục tọa độ Oxy đồ thị của hai h&agrave;m số tr&ecirc;n</span></li>

</ol>

<p><span data-contrast="none">* Vẽ đồ thị h&agrave;m số y = -2x (d</span><span data-contrast="none"><span data-fontsize="40">1</span></span><span data-contrast="none">) </span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:6,&quot;335551620&quot;:6,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:360}">&nbsp;</span></p>

<p><span data-contrast="none">Cho x = 1 </span><span data-contrast="none">&rarr;</span><span data-contrast="none"> y = -2 </span><span data-contrast="none">&rarr;</span><span data-contrast="none"> đồ thị h&agrave;m số đi qua điểm M(1; -2)</span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:6,&quot;335551620&quot;:6,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:360}">&nbsp;</span></p>

<p><span data-contrast="none">Cho x = 0 </span><span data-contrast="none">&rarr;</span><span data-contrast="none"> y = 0 </span><span data-contrast="none">&rarr;</span><span data-contrast="none"> đồ thị h&agrave;m số đi qua điểm O(0; 0) </span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:6,&quot;335551620&quot;:6,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:360}">&nbsp;</span></p>

<p><span data-contrast="none">* Vẽ đồ thị h&agrave;m số y = x (d</span><span data-contrast="none"><span data-fontsize="40">2</span></span><span data-contrast="none">)</span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:6,&quot;335551620&quot;:6,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:360}">&nbsp;</span></p>

<p><span data-contrast="none">Cho x = 1 </span><span data-contrast="none">&rarr;</span><span data-contrast="none"> y = 1 </span><span data-contrast="none">&rarr;</span><span data-contrast="none"> đồ thị h&agrave;m số đi qua điểm N(1; 1)</span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:6,&quot;335551620&quot;:6,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:360}">&nbsp;</span></p>

<p><span data-contrast="none">Cho x = 0 </span><span data-contrast="none">&rarr;</span><span data-contrast="none"> y = 0 </span><span data-contrast="none">&rarr;</span><span data-contrast="none"> đồ thị h&agrave;m số đi qua điểm O(0; 0)</span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:6,&quot;335551620&quot;:6,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:360}">&nbsp;</span></p>

<p><strong><span data-contrast="none">B&agrave;i 3. </span></strong><span data-contrast="none">a) Vẽ tr&ecirc;n c&ugrave;ng một hệ trục tọa độ Oxy đồ thị của hai h&agrave;m số tr&ecirc;n</span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:6,&quot;335551620&quot;:6,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:360}">&nbsp;</span></p>

<ol>

<li><span data-contrast="none">b) Qua điểm H(0; 4) vẽ đường thẳng d song song với trục Ox, cắt c&aacute;c đường thẳng y = 2x v&agrave; y = x lần lượt tại A v&agrave; B. T&igrave;m tọa độ của A v&agrave; B</span></li>

</ol>

<p><span data-contrast="none">Đường thẳng d</span><span data-contrast="none"><span data-fontsize="40">3</span></span><span data-contrast="none"> đi qua H v&agrave; song song với Ox c&oacute; phương tr&igrave;nh y = 4 Điểm A </span><span data-contrast="none">&isin;</span><span data-contrast="none"> (d</span><span data-contrast="none"><span data-fontsize="40">3</span></span><span data-contrast="none">) </span><span data-contrast="none">&rarr;</span><span data-contrast="none"> y</span><span data-contrast="none"><span data-fontsize="40">A</span></span><span data-contrast="none"> = 4, A thuộc đồ thị h&agrave;m số y = -2x </span><span data-contrast="none">&rarr;</span><span data-contrast="none"> 4 = -2x</span><span data-contrast="none"><span data-fontsize="40">A</span></span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:1,&quot;335551620&quot;:1,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:360}">&nbsp;</span></p>

<p><span data-contrast="none">&rarr;</span><span data-contrast="none"> x</span><span data-contrast="none"><span data-fontsize="40">A</span></span><span data-contrast="none"> = -2. Vậy A(-2; 4)</span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:1,&quot;335551620&quot;:1,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:360}">&nbsp;</span></p>

<p><span data-contrast="none">Điểm B </span><span data-contrast="none">&isin;</span><span data-contrast="none"> (d</span><span data-contrast="none"><span data-fontsize="40">3</span></span><span data-contrast="none">) </span><span data-contrast="none">&rarr;</span><span data-contrast="none"> y</span><span data-contrast="none"><span data-fontsize="40">B</span></span><span data-contrast="none"> = 4, B thuộc đồ thị h&agrave;m số y = x </span><span data-contrast="none">&rarr;</span><span data-contrast="none"> 4 = x</span><span data-contrast="none"><span data-fontsize="40">B </span></span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:6,&quot;335551620&quot;:6,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:360}">&nbsp;</span></p>

<p><span data-contrast="none">&rarr;</span><span data-contrast="none"> x</span><span data-contrast="none"><span data-fontsize="40">B</span></span><span data-contrast="none"> = 4. Vậy B(4; 4)</span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:6,&quot;335551620&quot;:6,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:360}">&nbsp;</span></p>

<p><strong><span data-contrast="none">B&agrave;i 3. </span></strong><span data-contrast="none">b)</span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:6,&quot;335551620&quot;:6,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:360}">&nbsp;</span></p>

<p><strong><span data-contrast="none">B&agrave;i 4. </span></strong><span data-contrast="none">a) Tr&ecirc;n mặt phẳng tọa độ vẽ đường thẳng d đi qua O(0 ; 0) v&agrave; A</span><span data-contrast="auto">(-1/2;3/2)</span> <span data-contrast="none">&nbsp;&nbsp;</span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335551550&quot;:6,&quot;335551620&quot;:6,&quot;335559685&quot;:-20,&quot;335559737&quot;:-20,&quot;335559738&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:360}">&nbsp;</span></p>

<p><span data-contrast="auto">...</span><span data-ccp-props="{}">&nbsp;</span></p>