Помогите раскрыть скобки:

(x+5) (x-7) + (2x-5) (x-1) + 30-12x=0

1) (x + 5) (x - 7) = x^2 - 7x + 5x - 35 = x^2 - 2x - 35

2) (2x - 5) (x - 1) = 2x^2 - 2x - 5x + 5 = 2x^2 - 7x + 5

3) x^2 - 2x - 35 + 2x^2 - 7x + 5 + 30 - 12x = 3x^2 - 9x - 30 + 30 - 12x = 3x^2 - 21x

4) 3x^2 - 21x = 0

3x (x - 7) = 0

3x = 0

X = 0

X - 7 = 0

X = 7

Ответ 0; 7