Do \(\left(x-2\right)^2>0\) nên \(\left(x+1\right).\left(x-4\right)< 0\)
\(\left\{{}\begin{matrix}x+1>0\\x-4< 0\end{matrix}\right.hoặc\left\{{}\begin{matrix}x+1< 0\\x-4>0\end{matrix}\right.\)
\(\left\{{}\begin{matrix}x>-1\\x< 4\end{matrix}\right.hoặc\left\{{}\begin{matrix}x< -1\\x>4\end{matrix}\right.\)
\(\left(x-2\right)^2\left(x+1\right)\left(x-4\right)< 0\)
⇔\(\left[{}\begin{matrix}\left\{{}\begin{matrix}x+1>0\\x-4< 0\end{matrix}\right.\\\left\{{}\begin{matrix}x+1< 0\\x-4>0\end{matrix}\right.\end{matrix}\right.\) ⇔\(\left[{}\begin{matrix}\left\{{}\begin{matrix}x>-1\\x< 4\end{matrix}\right.\\\left\{{}\begin{matrix}x< -1\\x>4\end{matrix}\right.\end{matrix}\right.\) ⇔ \(x< 4\)