\(\Rightarrow\left[{}\begin{matrix}x+2=0\\x-4=0\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=-2\\x=4\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}x+2=0\\x-4=0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=-2\\x=4\end{matrix}\right.\)