Question

(3x-2)²  = (x+7)²

Answer 1

\(\left(3x-2\right)^2=\left(x+7\right)^2\)

\(\Rightarrow\left[{}\begin{matrix}3x-2=x+7\\3x-2=-\left(x+7\right)\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}3x-x=7+2\\3x-2=-x-7\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}2x=9\\3x+x=-7+2\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x=\dfrac{9}{2}\\4x=-5\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x=\dfrac{9}{2}\\x=-\dfrac{5}{4}\end{matrix}\right.\)

Vậy: \(S=\left\{-\dfrac{5}{4};\dfrac{9}{2}\right\}\)

Answer 2

=>3x-2=x+7 hoặc 3x-2=-x-7

=>2x=9 hoặc 4x=-5

=>x=-5/4 hoặc x=9/2