Câu 1.31:
a. 2x + $\frac{1}{2}$ = $\frac{7}{9}$
=>2x = $\frac{7}{9}$ - $\frac{1}{2}$ = > 2x = $\frac{14}{18}$ - $\frac{9}{18}$=> 2x = $\frac{5}{18}$=> x= $\frac{5}{18}$ . $\frac{1}{2}$=> x= $\frac{5}{36}$
b. $\frac{3}{4}$ - 6x = $\frac{7}{13}$
=>$\frac{3}{4}$ - $\frac{7}{13}$ = 6x=> $\frac{39}{52}$ - $\frac{28}{52}$ = 6x => $\frac{11}{52}$= 6x = > x= $\frac{11}{52}$. $\frac{1}{6}$=> x= $\frac{11}{312}$