9 + y = 3x....y = 3x - 9 6y = -3x - 12 6(3x - 9) = -3x - 12 18x - 54 = -3x - 12 18x + 3x = -12 + 54 21x = 42 x = 42/21 x = 2 9 + y = 3x 9 + y = 3(2) 9 + y = 6 y = 6 - 9 y = -3 solution is (2,-3) <==