Question

\(\left\{{}\begin{matrix}3.\left(x-y\right)-y=11\\x-2\left(x+5y\right)=-15\end{matrix}\right.\)

Answer 1

\(\left\{{}\begin{matrix}3\left(x-y\right)-y=11\\x-2\left(x+5y\right)=-15\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}3x-3y-y=11\\x-2x-10y=-15\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}3x-4y=11\\-x-10y=-15\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}3x-4y=11\\x+10y=15\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}x=5\\y=1\end{matrix}\right.\)