Question

4x+4y=0 2x+y=-2 Solve the linear system by using subtitution

Answer 1

$4x+4y=0$
$2x+y=-2$

We'll use $2x+y=-2$⇒$y=-2x-2$

Plug into the other formula:
$4x+4(-2x-2)=0$
⇒$4x-8x-8=0$
⇒$-4x-8=0$
⇒$-4x=8$
⇒$x=-2$

Plug $x$ in to get $y$:
$y=-2(-2)-2$
⇒$y=4-2$
⇒$y=2$

So our solution is $x=-2$, $y=2$