7(х+6)+3х=72
7х+42+3х=72
10х=72-42
10х=30
х=3
7(х+1)-5(х-5)=12
7х+7-5х+25=12
2х=12-25-7
2х=-20
х=-10
х2 +3(х-3) =2(х+1)+х2
х2+3х-9=2х+2+х2
х2+3х-2х-х2=2+9
х=11
5(4х-3)-7(3х+1)=х
20х-15-21х-7-х=0
-2х=-22
х=11
(6х+1)/3-(х-12)/4=1/3
4(6х+1)-3(х-12)=4
24х+4-3х+36=4
21х=4-40
21х=-36
х=-36/21
х=-12/7
х=-1 5/7
(6х-5)/5-(3х+4)/4=1/4
4(6х-5)-5(3х+4)=5
24х-20-15х-20=5
9х=5+40
9х=45
х=5