\(\left\{{}\begin{matrix}5x-y=3\\-10x+2y=-6\end{matrix}\right.\)
=>\(\left\{{}\begin{matrix}10x-2y=6\\-10x+2y=-6\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}10x-2y-10x+2y=6-6=0\\5x-y=3\end{matrix}\right.\)
=>\(\left\{{}\begin{matrix}0x=0\\y=5x-3\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x\in R\\y=5x-3\end{matrix}\right.\)