Пошаговое объяснение:

1 5/7 - х/49 = 43/49

х/49 = 1 5/7 - 43/49

х/49 = 1 35/49 - 43/49

х/49 = 84/49 - 43/49

х/49 = 41/49

х = 41/49 * 49

х = 41/1 * 1

х = 41/1

х = 41