Помогите пожалуйста !!! Нужны 7,8,10,12,14. Заблаговременно огромное спасибо!Даю 70 баллов!

7) 7x = (2x + 1) + 3x - 5
7x = 4x + 4x + 1 + 3x - 5
7x = 7x + 4x - 4
4x - 4 = 0
4x = 4
x = 1
Ответ: x = 1.

8) (x + 3)(x - 2) - (x - 3)(x + 2) - 5 = 6x - 7
(x - 2x + 3x - 6) - (x + 2x - 3x - 6) - 5 = 6x - 7
x + x - 6 - x + x + 6 - 5 = 6x - 7
2x - 5 = 6x - 7
6x - 2x = -5 + 7
4x = 2
x = 0,5
Ответ: x = 0,5.

10) x + 2x - 9x - 18 = 0
x(x + 2) - 9(x + 2) = 0
(x - 9)(x + 2) = 0
(x - 3)(x + 3)(x + 2) = 0
x - 3 = 0  x = 3
x + 3 = 0  x = -3
x + 2 = 0  x = -2
Ответ: x = -3; -2; 3.

12) (5 - x) - (3x - 2)(2x + 1) = x(2 - 5x)
25 - 10x + x - (6x + 3x - 4x - 2) = 2x - 5x
25 - 10x + x - 6x + x + 2 = 2x - 5x
-5x + 27 - 9x = 2x - 5x
27 -  9x = 2x
11x = 27
x = 27/11 = 2 6/11
Ответ: x = 27/11. 

14) 2x - 1 - 3x - 5 = 2 - 2(3x - 1) - 2x
2x - 1 - 3x - 5 = 2 - 6x + 2 - 2x
2x - 1 - 3x - 5 = 4 - 8x
2x - 1 - 3x + 8x = 4 + 5
2x - 1 + 5x = 9
1. Раскрываем со знаком "+" (x  1):
2(x - 1) + 5x = 9
2x - 2 + 5x = 9
7x = 9 + 2
x = 11/7 
2. Со знаком "-" (x lt; 1):
-2(x - 1) + 5x = 9
-2x + 2 + 5x = 9
3x = 7
x = 7/3 - не подходит
Ответ: x = 11/7.