Question

How do you solve

-x +y=-5
-3x+4y=-12

Answer 1

`-x+y=-5|\cdot(-3)\\ -3x+4y=-12\\\\ 3x-3y=15\\ \underline{-3x+4y=-12}\\ y=3\\\\ -x+3=-5\\ -x=-8\\ x=8\\\\ \boxed{x=8,y=3}`

Answer 2

`\left \{ {{-x+y=-5} \ \ |(-4) \atop {-3x+4y=-12}} \right. \\\\ \left \{ {{4x-4y=20} \atop {-3x+4y=-12}} \right. \\ ======== \\ \boxed{x \ / =8} \\\\ -x+y=-5 \\\\ -8+y=-5 \\\\ y=-5+8 \\\\ \boxed{y=3}`