Tính: a) -16/20 . (-12) b) (5/4)^2 c) (6/-8)^2

* Hướng dẫn giải

$\begin{array}{l}a)\frac{-16}{20}.(-12)=24\\ b){\left(\frac{5}{4}\right)}^2\text{=}\frac{25}{16}\\ c){\left(\frac{6}{-8}\right)}^2\text{=}\frac{9}{16}\end{array}$