Answer
The required value is $x=-6,y=-2$
Work Step by Step
We have to multiply the second equation with 7 and add it to the first equation:
$\begin{align}
& 2x-7y+7\left( 3x+y \right)=2+7\left( -20 \right) \\
& 2x-7y+21x+7y=2-140 \\
& 23x=-138 \\
& x=-6
\end{align}$
Substitute the value of $x=-6$ in the first equation:
$\begin{align}
& 2\left( -6 \right)-7y=2 \\
& -12-7y=2 \\
& -7y=14 \\
& y=-2
\end{align}$
