Пошаговое объяснение:
2/3х = 3 1/21 + 1 5/7
2/3х = 3 1/21 + 1 15/21
2/3х = 4 16/21
х = 4 16/21 : 2/3
х = 100/21 * 3/2
х = 50/7 * 1/1
х = 50/7
х = 7 1/7
Пошаговое объяснение:
2/3х = 3 1/21 + 1 5/7
2/3х = 3 1/21 + 1 15/21
2/3х = 4 16/21
х = 4 16/21 : 2/3
х = 100/21 * 3/2
х = 50/7 * 1/1
х = 50/7
х = 7 1/7