\(\left|x^2-2x-2\right|=5\)
\(\Leftrightarrow\left[{}\begin{matrix}x^2-2x-2=5\\x^2-2x-2=-5\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}\left(x-1\right)^2-3=5\\\left(x-1\right)^2-3=-5\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}\left(x-1\right)^2=8\\\left(x-1\right)^2=-2\end{matrix}\right.\)
\(\Leftrightarrow\left(x-1\right)^2=8\)
\(\Leftrightarrow x-1=\sqrt{8}\)
\(\Leftrightarrow x=\sqrt{8}+1\)
\(\Leftrightarrow x\approx3,8\)
Vậy : \(x\approx3,8\)
P/s : Không chắc chắn lắm vì kết quả khá xấu .