1) НОЗ(7,3)=21
3(х+9)=21+7(х+1)
3х+27=21+7х+7
3х-7х=28-27
-4х=1
х=-1/4
2) НОЗ(6,9)=18
18-3(5х-2)=2(х-5)
18-15х+6=2х-10
24+10=2х+15х
17х=34
х=2
3) НОЗ(5,2)=10
2(3х+4)+5(х-7)=4(2х+3)
6х+8+5х-35=8х+12
11х-8х=12+35-8
3х=39
х=13
4) НОЗ(2,3)=6
3(7х-3)-2(9-4х)=3(7-х)
21х-9-18+8х=21-3х
29х+3х=21+18+9
32х=48
х=1,5