Решмте уравнение: х-7/15 / 3/4-1/2=-4

 Х - 7/15 : 3/4 - 1/2 = -4;

Х – 7/15 * 4/3 – 1/2 = -4;

Х - (7 * 4)/(15 * 3) – 1/2 = -4;

Х - 28/45 – 1/2 = -4;

Х = -4 + 28/45 + 1/2;

Х = - 4 + (28 * 2)/(45 * 2) + (1 * 45)/(2 * 45);

Х = -4 + 56/90 + 45/90;

Х = -4 + 101/90;

Х = -4 + 1 11/90;

Х = -3 90/90 + 1 11/90;

Х = -2 79/90.

Проверка:

 -2 79/90 - 7/15 : 3/4 - 1/2 = -4;

-2 79/90  - 7/15 * 4/3 – 1/2 = -4;

-2 79/90 - (7 * 4)/(15 * 3) – 1/2 = -4;

-2 79/90 - 28/45 – 1/2 = -4;

-2 79/90 – (28 * 2)/(45 * 2) – 1/2 = -4;

-2 79/90 – 56/90 – 1/2 = -4;

-3 45/90 – 1/2 = -4;

-3 1/2 – 1/2 = -4;  

 -3 2/2 = -4;

-4 = -4. Решение выполнено верно.