Ответ:

Пошаговое объяснение:

1)

x - 4 3/7 = 3 5/6;

x = 3 5/6 + 4 3/7

x = 3 35/42 + 4 18/42

x = 7 53/42

x = 8 11/42

2)

x-18 1/5 = 2 7/15;

x = 2 7/15 + 18 1/5

x = 2 7/15 + 18 3/15

x = 20 10/15

x = 20 2/3

3)

(x-9 3/7) + 5 8/21 = 6 5/14;

x - 9 3/7 + 5 8/21 = 6 5/14

x = 6 5/14 + 9 3/7 - 5 8/21

x = 6 15/42 + 9 18/42 - 5 16/42

x = 10 17/42