\(\Leftrightarrow\left\{{}\begin{matrix}2x^2-8x>=0\\x^2-4x+5=4x^2\left(x-4\right)^2\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}x\left(x-4\right)>=0\\4x^2\left(x-4\right)^2-x\left(x-4\right)-5=0\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}x>=4;x< =0\\4x^2\left(x-4\right)^2+4x\left(x-4\right)-5x\left(x-4\right)-5=0\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}x>=4;x< =0\\4x\left(x-4\right)\left[x\left(x-4\right)+1\right]-5\left(x^2-4x+1\right)=0\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}x>=4;x< =0\\\left(x^2-4x+1\right)\left(4x^2-16x-5\right)=0\end{matrix}\right.\)
hay \(x=\dfrac{4\pm\sqrt{21}}{2}\)
