what is 4x + 8y = 20
-4x + 2y = -30
(4x+8y)-(4x-2y)=20-30
10y=-10
y=-1
4x-8=20
x=7
4x + 8y = 20
Adding the two equations, we get
10y = -10 which implies that y = -1
Subbing this into the first equation, we have
4x + 8(-1) = 20
4x - 8 = 20 add 8 to both sides
4x = 28 divide both sides by 4
x = 7
So...(x, y) = (7, -1)