8 1/3 - ( 5 2/15 - х) = 3 2/9
8 1/3 - 5 2/15 + х = 3 2/9
8 5/15 - 5 2/15 + х = 3 2/9
3 3/15 + х = 3 2/9
3 1/5 + х = 3 2/9
х= 3 2/9 - 3 1/5 = 3 10/45 - 3 9/45
х = 1/45
проверим:
8 1/3 - ( 5 2/15 - 1/45) = 3 2/9
8 1/3 - ( 5 6/45 - 1/45) = 3 2/9
8 1/3 - 5 5/45 = 3 2/9
8 3/9 - 5 1/9 = 3 2/9
3 2/9 = 3 2/9