1) 87 / (4х + 5) = 3
87 = 3 * (4х + 5)
29 = 4х + 5
29 - 5 = 4х
4х = 24
х = 24/4
х = 6
2)17 * (3х - 16) = 85
3х - 16 = 5
3х = 5 + 16
3х = 21
х = 21 / 3
х = 7
3) 9 * (6х - 13) = 153
6х - 13 = 17
6х = 17 + 13
6х = 30
х = 30 / 6
х = 5
4) 3 * (8х + 51) = 201
8х + 51 = 67
8х = 67 - 51
8х = 16
х = 16 / 8
х = 2
5) (46х - 57) / 3 = 27
46х - 57 = 27 * 3
46х = 81 + 57
46х = 138
х = 138 / 46
х = 3
6) (19х + 62) / 15 = 13
19х + 62 = 13 * 15
19х = 195 - 62
19х = 133
х = 133/19
х = 7