Решите уравнение 1) 9x+(7x+5)-(2x-3)=x+7 2) 3x-(8+9x)-(5x-4)=-7x 3)x-15,5+8x-(13x+16,5)=12x 4) 6x-(2x+13)-(x-7)=15x

Решим уравнения:

1) 9 * x + (7 * x + 5) - (2 * x - 3) = x + 7; 

9 * x + 7 * x + 5 - 2 * x + 3 = x + 7;

16 * x + 5 - 2 * x + 3 = x + 7;

14 * x + 8 = x + 7;

14 * x - x = 7 - 8;

13 * x = -1;

x = -1/13.

2) 3 * x - (8 + 9 * x) - (5 * x - 4) = -7 * x; 

3 * x - 8 - 9 * x - 5 * x + 4 = -7 * x; 

-6 * x - 8 - 5 * x + 4 = -7 * x;

-11 * x - 4 = -7 * x;

-11 * x + 7 * x = 4;

-4 * x = 4;

x = -4/4;

x = -1.

3) x - 15,5 + 8 * x - (13 * x + 16,5) = 12 * x; 

x - 15.5 + 8 * x - 13 * x - 16.5  = 12 * x; 

9 * x - 13 * x - 32 = 12 * x;

-4 * x - 32 = 12 * x;

-4 * x - 12 * x = -32;

16 * x = 32;

x = 2.

4) 6 * x - (2 * x + 13) - (x - 7) = 15 * x; 

6 * x - 2 * x - 13 - x + 7 = 15 * x; 

3 * x - 6 = 15 * x; 

3 * x - 15 * x = 6; 

-12 * x = 6; 

x = -6/12; 

x = -1/2.