Verified answer

4,2х+8=8-7х

4,2х+7х=8-8

11,2х=0

х=0

 -27х=5-54х

-27х+54х=5

27х=5

х=5/27

х-1=0,4х-2,5

х-0,4х=-2,5+1

0,6х=-1,5

х=-1,5/0,6

х=-2,5