1/3x + y = 9
y = -1/3x + 9
-2x + 2y = -6
-2x + 2(-1/3x + 9) = -6
-2x - 2/3x + 18 = -6
-6/3x - 2/3x = -6 - 18
-8/3x = -24
x = -24 * -3/8
x = 9 <== here is y
-2x + 2y = -6
-2(9) + 2y = -6
-18 + 2y = -6
2y = -6 + 18
2y = 12
x = 12/2
x = 6 <=== here is x
