а) $$5(4x - 2) - 15x = 20x - 10 - 15x = 5x - 10$$.
б) $$-3(2 - x) + 8 = -6 + 3x + 8 = 3x + 2$$.
в) $$6x - 4 + 2(3 - x) = 6x - 4 + 6 - 2x = 4x + 2$$.
г) $$2x - 4(3x - 1) = 2x - 12x + 4 = -10x + 4$$.