решите пж желая бы 1 и 2 номера упрашиваю осталось приблизительно

1) 5a(a - 6a + 3) = 5a - 30a + 15a
(x + 4)(3x - 2) = 3x - 2x + 12x - 8 = 3x + 10x - 8
(6m + 5n)(7m - 3n) = 42m - 18mn + 35mn -15n = 42m + 17mn - 15n
(x + 5)(x + x - 6) = x + x - 6x + 5x + 5x - 30 = x + 6x - x - 30
2) 18xy - 6x = 6x(3y - x)
15a - 3a = 3a(5a - 1)
4x - 4y + cx - cy = (4x - 4y) + ( cx - cy) = 4(x - y) + c(x - y) = (x - y)(4 + c)
3) 3x + 9x = 0
3x(x + 3) = 0
x(x + 3) = 0
либо x = 0       или    x + 3 = 0
                                x = - 3
Ответ: - 3 ; 0
4) 7b(2b + 3) -(b + 6)(b - 5)= 7b + 21b - b + 5b - 6b + 30 = 6b + 20b + 30