(4.9+3.5х)(7х-2.8)=0
(4.9+3.5х)(7х-2.8)=0 34,3х-13,72+24,5-9,8х=0 24,5х=-10,78 х=-0,44
34.3х-13.72+24.5-9.8х=0
24.5х=-10.78
х=-0.44