x=5y-2, x+5y=-12
x=5y-2, 5y-2+5y=-12
x=5y-2, 10y=-10
x=5y-2, y=1
x=3, y=1
x-5y=-2
x+5y=-12
x=-2+5y
(-2+5y)+5y=-12
-2+5y+5y=-12
10y=-10
y=-1
x=-7
x=5y-2, x+5y=-12
x=5y-2, 5y-2+5y=-12
x=5y-2, 10y=-10
x=5y-2, y=1
x=3, y=1
x-5y=-2
x+5y=-12
x=-2+5y
(-2+5y)+5y=-12
-2+5y+5y=-12
10y=-10
y=-1
x=-7