2x + y = 12
x = 9 - 2y
x + 2y = 9
2x + 4y = 20
x + 3y = 16
2x - y = 11
y = 11 - 2x
4x - 3y = -13
y = 10 + x
-3x + 3y = 30
2x + y = 11
x-2y=-7
x = 2, y = 7
x = 5, y = 2
>
x= 3, y=5
x = 7, y=3