$ \dfrac{2^5.7+2^5}{2^5.5^2-2^5.3} $
$=\dfrac{2^5.(7+1)}{2^5.(5^2-3)} $
$=\dfrac{8}{22} = \dfrac{4}{11} $
$\dfrac{3^4.5-3^6}{3^4.13+3^4} $
$=\dfrac{3^4.(5-3^2)}{3^4.(13+1)} $
$=\dfrac{5-3^2}{13+1} $
$=\dfrac{-4}{14} = \dfrac{-2}{7} $
Quy đồng : $\dfrac{4}{11} = \dfrac{28}{77} $
$\dfrac{-2}{7} = \dfrac{-22}{77} $
Chúc em học tốt nhé !