2х-х=1+5
х=6
3х-15=х+3
3х-х=3+15
2х=18
х=18:2
х=9
7х+42=20х+16
7х-20х=16-42
-13х= -26
х= -26:(-13)
х=2
1,5х+12= -4х+1
1,5х+4х=1-12
5,5х= -11
х= -11:5,5
х= -2
1/6х+3/2= -1/3х
1/6х+1/3х= -3/2
1/2х= -3/2
х= -3/2:1/2
х= -3/2*2
х= -3
3/4х+6=2х+1
3/4х-2х=1-6
-1 1/4х= -5
- 5/4х= -5
х= -5:(-5/4)
х= -5*(-4/5)
х=4