Question

(X+2)^2 =25

Answer 1

\(\left(x+2\right)^2=25\)

\(\left(x+2\right)^2=5^2\)

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

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

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

Vậy x = 3 hoặc -7

Answer 2

\(\left(x+2\right)^2=25\\ \Leftrightarrow\left(x+2\right)^2=\left(\pm5\right)^2\\ \Rightarrow\left\{{}\begin{matrix}x+2=5\\x+2=-5\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=3\\x=-7\end{matrix}\right.\)

Vậy ....

Answer 3

\(\left(x+2\right)^2=25\Leftrightarrow x+2=\pm5\)

\(\Leftrightarrow\left[{}\begin{matrix}x+2=5\\x+2=-5\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=3\\x=-7\end{matrix}\right.\)

Answer 4

\(\left(x+2\right)^2=25\)→ \(\left(x+2\right)^2=5^2\)

→x + 2 = 5→x = 3

Answer 5

\(\left(x+2\right)^2=25=5^2=\left(-5\right)^2\)

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

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

Vậy : \(x\in\left\{3,-7\right\}\)