7 5/24 - х = 2 5/16
х = 7 5/24 - 2 5/16
х = 7 10/48 - 2 15/48 = 6 58/48 - 2 15/48
х = 4 43/48
32:b = 64:8
32:b = 8
b = 32:8
b = 4
Проверка:
32:4 = 64:8
8=8