25 + ( x - 2 ) * 15 =70 72

1) 25 + (x - 2) * 15 = 70; 

15 * (x - 2) = 70 - 25;

15 * (x - 2) = 45;

x - 2 = 45/15;

x - 2 = 3;

x = 3 + 2;

x = 5;

Проверка:

25 + (5 - 2) * 15 = 70; 

25 + 3 * 15 = 70; 

25 + 5 = 70;

70 = 70;

Верно;

Ответ: х = 5.

2) 72/(12 - x/4) = 9; 

9 * (12 - x/4) = 72; 

12 - x/4 = 72/9; 

12 - x/4 = 8;  

-x/4 = 8 - 12; 

-x/4 = -4; 

x/4 = 4; 

x = 4 * 4; 

x = 16; 

Проверка: 

72/(12 - 16/4) = 9; 

72/(12 - 4) = 9; 

72/8 = 9; 

9 = 9; 

Правильно; 

Ответ: х = 16.