Verified answer

3)-5х-5=10х+15

-20=15х

х=-20/15

х=-4/3

х=-1 1/3

5)4*(2х-3)=10+2х

8х-12=10+2х

6х=22

х=22/6

х=11/3

х=3 2/3

6) 10*(х-3)=5*(х+4)

10х-30=5х+20

5х=50

х=50/5

х=10