Ответ:

Пошаговое объяснение:

5 4/7 + (4 6/7 + x) = 10 3/7

5 4/7 + 4 6/7 + x = 10 3/7

9 10/7 + x = 10 3/7

x = 10 3/7 - 9 10/7

x = 10 3/7 - 10 3/7

x = 0