1) 9(х-1) = х+15
9х - 9 = х + 15
9х - х = 15 + 9
8х = 24
х = 3
2) (11х + 14) - (5х - 8) = 25
11х + 14 - 5х + 8 = 25
6х = 3
х = 0,5
3) 12 - 4(х - 3) = 39 - 9х
12 - 4х +12 = 39 - 9х
5х = 15
х = 3
4) 2(3х + 5) - 3(4х -1) = 11,8
6х + 10 - 12х + 3 = 11,8
-6х = -1,2
х = 0,2