а) a+(2-a) = a + 2 - a = 2
б) 9x - (8x - (1-2x)) = 9x - 8x + 1 - 2x = -x + 1
в) 4ab - (3ab - (2ab - (ab + 1))) = 4ab - 3ab + 2ab - ab - 1 = 2ab - ab - 1 = ab - 1
а) a+(2-a) = a + 2 - a = 2
б) 9x - (8x - (1-2x)) = 9x - 8x + 1 - 2x = -x + 1
в) 4ab - (3ab - (2ab - (ab + 1))) = 4ab - 3ab + 2ab - ab - 1 = 2ab - ab - 1 = ab - 1