Пошаговое объяснение:
18/30 - х = 4/30 +6/30
18/30 - х = 10/30
х= 18/30 - 10/30
х= 8/30
х = 4/15
(13/67 + 6/67) - х = 9/67
19/67 - х = 9/67
х = 19/67 - 9/67
х= 10/67
10/15 + ( 5/15 - х ) = 14/15
10/15 + 5/15 - х = 14/15
15/15 - х= 14/15
х= 15/15 - 14/15
х= 1/15
