a) $7\times \sqrt{0.36}-5 \times\sqrt{25} = 7\times0.6-5\times5 = 4.2-25=-20.8$
b) $11 \times\sqrt{1.69}+3\times \sqrt{0.01} = 11\times1.3+3\times0.1=14.3+0.3=14.6$
c) $3\times \sqrt{\frac{1}{9}}+1.5 \times\sqrt{225}=3\times \frac{1}{3}+1.5\times15= 1+22.5=23.5$
d) $0.1\times \sqrt{100}-\sqrt{\frac{4}{25}}=0.1\times10-\frac{2}{5} =1-0.4=0.6$