1. 1/21-b=29/42
22/21-b=29/42
-b=29/42 - 22/21
-b= - 5/-14
b= 5/14
b = 5/12
Пошаговое объяснение:
1 1/21 - b = 29/42
b = 22/21 - 29/42
b = 15/42 = 5/12
Проверяем:
1 1/21 - 5/12 = 29/42
22/21 - 5/12 = 29/42
29/42 = 29/42
