Question

(2.x-1)²=25

Answer 1

\(\left(2x-1\right)^2=25\)

\(\Rightarrow\left(2x-1\right)^2=5^2\)

\(\Rightarrow\left[{}\begin{matrix}2x-1=5\\2x-1=-5\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}2x=5+1\\2x=-5+1\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}2x=6\\2x=-4\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x=\dfrac{6}{2}\\x=-\dfrac{4}{2}\end{matrix}\right.\)

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

Vậy: \(S=\left\{3;-2\right\}\)

Answer 2

=>2x-1=5 hoặc 2x-1=-5

=>2x=6 hoặc 2x=-4

=>x=-2 hoặc x=3