1) х - 7/8 = 11/12
х = 11/12 + 7/8
х = 22/24 + 21/24
х = 43/24
х = 1 19/24
2) 7/12 - х = 11/24
х = 7/12 - 11/24
х = 14/24 - 11/24
х = 3/24
х = 1/8
3) х - 2/5 = 3/7 - 8/35
х - 2/5 = 15/35 - 8/35
х - 2/5 = 7/35
х - 2/5 = 1/5
х = 1/5 + 2/5
х = 3/5
4) 3 - х = 2/7
х = 3 - 2/7
х = 2 7/7 - 2/7
х = 2 5/7
5) х + 2/9 = 5/6
х = 5/6 - 2/9
х = 15/18 - 4/18
х = 11/18
6) х - 1/6 = 3/8
х = 3/8 + 1/6
х = 9/24 + 4/24
х = 13/24