А) 8.3/4 - х = 3.5/16
х = 8.3/4 - 3.5/16
х = 8.12/16 - 3.5/16
х = 5.7/16
б) х:7/15-15/28
х = 7/15*15/28
х = 1/4
в) х - 4.3/7 = 3.5/6
х = 4.3/7+3.5/6
х = 4.18/42 + 3.35/42
х = 8.11/42
г) х - 2.7/8 + 3.5/6 = 4.2/3
х = 4.2/3 - 3.5/6 + 2.7/8
х = 4.16/24 - 3.20/24 + 2.21/24
х = 3.17/24
P.S.: 3.1/2(три целых одна вторая)(это пример:))