0,3х+8=2
4х+7=5
3х+х+5х=2,1
0.3х+8=2 0.3х= -6 х=-6:0.3 х=-20 4х+7=5 4х=-2 х=-0.5 3х+х+5х=2.1 9х=2.1 х=2.1:9 х=0.23