4). Решить уравнения. a) (2x - 6)(8х + 5) + (3 - 4x)(3 + 4x) =55 б) (x + 2)(x + 1) - (x - 3)(x + 4) = 12
b) (- 4x + 1)(x- 1) - x = (5 - 2x)(2x + 3) - 17 г) (x + 10)(x - 5) - (x - 6)(x + 3) = 16 д) (2х - 3)(4х + 3) - 8x2 = 33
e) 21x2 - (3x - 7)(7x - 3) = 37