решить уравнение 56y-36y-9=153 (158u-21)*3+27=234 (36t+98)/14=25 (12x+30x+42)/6=21

Найдем корешки.

1) 56 * y - 36 * y - 9 = 153; 

56 * y - 36 * y = 153 + 9;

y * (56 - 36) = 162;

y * 20 = 162;

y = 162/20;

y = 8.1.

2) (158 * u - 21) * 3 + 27 = 234;  

(158 * u - 21) * 3 = 234 - 27; 

(158 * u - 21) * 3 = 207; 

(158 * u - 21) = 207/3; 

(158 * u - 21) = 69; 

158 * u = 69 + 21; 

158 * u = 90; 

u = 90/158. 

3) (36 * t + 98)/14 = 25; 

36 * t + 98 = 25 * 14;

36 * t + 98 = 350;

36 * t = 350 - 98;

36 * t = 252;

t = 252/36;

t = 7.

4) (12 * x + 30 * x + 42)/6 = 21; 

12 * x + 30 * x + 42 = 21 * 6; 

42 * x + 42 = 126; 

42 * x = 126 - 42; 

42 * x = 84; 

x = 84/42; 

x = 2; 

Ответ: х = 2.