Ответ:

Пошаговое объяснение:

-1/12 - 5/12 + (-7/12) = (-1-5-7) / 12 = - 13/12

- 3/8 * (- 1/9) * (- 8/3) = - 1/9

-15 * (1/5 - 2/3) = - 15 * (- 7/15) = 7

х * 3/7 + 2/5 * 3/7 = 1

3/7 * (х + 2/5) = 1

х + 2/5 = 1 : 3/7 = 1 * 7/3 = 7/3

х = 7/3 - 2/5 = 29/15

3/7 * 3/4 - 3/7 * (- 1/12) = 3/7 * (3/4 - (- 1/12)) = 3/7 * 5/6 = 5/14