\(g'\left(x\right)=2\left(x-1\right).f'\left(x^2-2x\right).\dfrac{1}{\left[f\left(x^2-2x\right)+1\right]^2}\)
\(g'\left(x\right)=0\Rightarrow\left[{}\begin{matrix}x=1\\x^2-2x=-2\left(vn\right)\\x^2-2x=-1\\x^2-2x=3\end{matrix}\right.\) \(\Rightarrow x=\left\{1;-1;3\right\}\)
C đúng