\(\left(x+2\right)^2=49\)
\(\Rightarrow\left[\begin{array}{nghiempt}\left(x+2\right)^2=7^2\\\left(x+2\right)^2=\left(-7\right)^2\end{array}\right.\)
\(\Rightarrow\left[\begin{array}{nghiempt}x+2=7\\x+2=-7\end{array}\right.\)
\(\Rightarrow\left[\begin{array}{nghiempt}x=7-2\\x=-7-2\end{array}\right.\)
\(\Rightarrow\left[\begin{array}{nghiempt}x=5\\x=-9\end{array}\right.\)
Vậy: \(x\in\left\{5;-9\right\}\)