4/15 + х = 11/15х = 11/15 - 4/15 = 7/15
16/21 - х = 9/2116/21 - 9/21 = хх = 7/21 = 1/3
х - 4/35 = 12/35х = 4/35 + 12/35 х = 16/35
4/15 + х = 11/15
х = 11/15 - 4/15 = 7/15
16/21 - х = 9/21
16/21 - 9/21 = х
х = 7/21 = 1/3
х - 4/35 = 12/35
х = 4/35 + 12/35
х = 16/35