Question

Tìm x biết:

\(x^2-4x+4=25\)

Answer 1

(x-2)² = 25 => x- 2 = 5
                  => x = 7

Answer 2

\(x^2-4x+4=25\)

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

\(\Leftrightarrow\orbr{\begin{cases}x-2=5\\x-2=-5\end{cases}}\)

\(\Leftrightarrow\orbr{\begin{cases}x=7\\x=-3\end{cases}}\)