(7,85х - 12,4)*(-1 9/91)= - 2 11/12 - 1 2/3

Решаем уравнение с одной переменной:

(7,85х - 12,4)(- 1 9/91) = - 2 11/12 - 1 2/3;

(7,85х - 12,4)(- 1 9/91) = - 2 11/12 - 1 8/12;

(7,85х - 12,4)(- 1 9/91) = - 3 19/12;

(7,85х - 12,4)(- 100/91) = - 55/12;

7,85х - 12,4 = - 55/12 / (- 100/91);

7,85х - 12,4 = - 55/12 х (- 91/100);

7,85х - 12,4 = - 11/12 х (- 91/20);

7,85х - 62/5 = 1001/240;

7,85х = 1001/240 + 62/5;

7,85х = 1001/240 + 2976/240;

157/20х = 3977/240;

х = 3977/240 / 157/20;

х = 3977/240 х 20/157;

х = 3977/12 х 1/157;

х = 3977/1884;

х 2,11;

Проверяем:

(7,85 х 2,11 - 12,4)(- 1 9/91) = - 2 11/12 - 1 2/3;

4,1635 х (- 100/91) = - 55/12;

4,1635 х (- 1,099) = - 55/12;

- 4,6 = - 4,6.