1) 7x/6-5x/18=4/27 2) 2x/7+x/4=15/14 3)- x/8+1= x/12

1) 
7х/6 - 5х/18 = 4/27
21х/18 - 5х/18 = 4/27
16х/18 = 4/27
16х=(18*4)/27
16х=72/27
х=18/27=6/9=2/3

2)
2х/7 + х/4 = 15/14
8х/28 + 7х/28 = 15/14
15х/28 = 15/14
15х = (28*15)/14
х = 28/14 = 2

3)
-х/8+1=х/12
х/8+х/12=1
3х/24+2х/24=1
5х/24=1
5х=24
х=24/5=4,8