Crying in absolute value symbol equation

Equation | 3x + y-12 | + | 4x-3y-3 | = 0 that satisfies all real numbers x, y for the value of x-y?

Absolute value to zero, tears eyes.

3x+y-12=0, 4x-3y-3=0

Solving the simultaneous equation, x=3, y=3.

Therefore x-y=0