(х- 9 3/7 ) + 5 8/21 = 6 5/16
х - 9 3/7 + 5 8/21 = 6 5/16
х - 9 9/21 + 5 8/21 = 6 5/16
х - 4 1/21 = 6 5/16
х= 6 5/16 + 4 1/21 = 6 105/336 + 4 16/336
х= 10 121/336
Проверим:
(10 121/336 -9 3/7 ) + 5 8/21 = 6 5/16
(10 121/336 - 9 144/336) + 5 8/21= 6 5/16
313/336 + 5 128/336 = 6 5/16
5 + 441/336 = 6 5/16
6 105/336 = 6 5/16
6 5/16 = 6 5/16