9x + 3y = 2
-9x - y = 0
Add the parts straight down. 9x added to -9x makes 0. 3y added to -y makes 2y. 2 added to 0 makes 2.
0x + 2y = 2
2y = 2
y = 1
Pick one of the equations (doesn't matter which one).
9x + 3y = 2
9x + 3(1) = 2
9x + 3 = 2
9x = -1
x = -1/9
Answer: x = -1/9, y = 1