6x - 4 - 2(5x - 11) = 6x - 4 - 10x + 22 = (6 - 10)x + (-4 + 22) = -4x + 18
6(x - 2) - (3x - 12) = 6x - 12 - 3x + 12 = (6 - 3)x + (-12 + 12) = 3x
x - 4 - 2(3x - 12) = x - 4 - 6x + 24 = (1 - 6)x + (-4 + 24) = -5x + 20
5(3x + 2) - 2(6x - 3) = 15x + 10 - 12x + 6 = (15 - 12)x + (10 + 6) = 3x + 16
9(2x - 20) - 6(3x - 30) = 18x - 180 - 18x + 180 = (18 - 18)x + (-180 + 180) = 0