б) 8х - 3х + х = (8 - 3 + 1)х = 6х

в) х - 2х + 7х = ( 1 - 2 + 7)х = 6х

г) 11х + х - 12х = (11 + 1 - 12)х =0х

д) - 5х + 5х + 3х = (-5 + 5 + 3) х =3х

е) -8х + 8х - х = (-8 + 8 - 1)х = - 1х