#### Answer

$x=-1$
$y=3$

#### Work Step by Step

First, we have to solve the second equation for $y$ and after that, we can substitute this expression in the first equation:
$4+7x=-y$
$-4-7x=y$
$6x-y=-9$
$6x-(-4-7x)=13x+4=-9$
$13x=-13$
$x=-1$
$-4-7x=-4-7(-1)=3=y$
We need to check, if it is the right solution, we substitute x with $-1$ and y with $3$:
$6(-1)-3=-9$ $\checkmark$
$4+7(-1)=-3$ $\checkmark$