12 х - х = 55 2 (х+3)= 16 5 (х+3)+7 =3 (х+12) 5х+ 15 + 7= 3х + 36

12х-х=55
11х=55
х=55:11
х=5

2(х+3)=16
2х+6=16
2х=16-6
2х=10
х=10:2
х=5

5(х+3)+7=3(х+12)
5х+15+7=3х+36
5х+22=3х+36
5х-3х=36-22
2х=14
х=14:2
х=7

5х+15+7=3х+36
5х+22=3х+36
5х-3х=36-22
2х=14
х=14:2
х=7

1)11x=55
x=55/11
x=5
2)2x+6=16
2x=22
x=22/2
x=11
3)5x+15+7=3x+36
2x=14
x=14/2
x=7
4)2x=14
x=14/2
x=7