0,6-1,6(х-4)=3(7-0,4х)
0.6-1.6х+5.2=21-1.4х -1.6х+1.4х=21-5.2-0.6 -0.2х=15.2 х=-76
0,6-1,6х+6,4=21-1,2х -0,4х=-7+(+21) -0,4х=14 х=-35