Solve the system of equations: 3x - y = 15 (x+6)/2 - y/3 = 6

1. Simplify the second equation: Multiply by 6 to get 3(x+6) - 2y = 36, which simplifies to 3x - 2y = 18.

2. Subtract the simplified second equation from the first equation: (3x - y) - (3x - 2y) = 15 - 18, which gives y = -3.

3. Substitute y = -3 into the first equation: 3x - (-3) = 15, so 3x = 12, and x = 4.

The solution is x = 4, y = -3.