CHÚC BẠN HỌC TỐT!!!
Trả lời:
$a, (2x-3)^2=16$
\(⇔\left[ \begin{array}{l}2x-3=4\\2x-3=-4\end{array} \right.\)\(⇔\left[ \begin{array}{l}x=\dfrac{7}{2}\\x=-\dfrac{1}{2}\end{array} \right.\)
Vậy $S=\{\dfrac{7}{2};-\dfrac{1}{2}\}$
$b, \bigg{(}-\dfrac{1}{3}\bigg{)}^3.x=\dfrac{1}{81}$
$⇔-\dfrac{1}{27}.x=\dfrac{1}{81}$
$⇔x=-\dfrac{1}{3}$
Vậy $S=\{-\dfrac{1}{3}\}$.