3.2×0.2+0.8=0.8*【0.8+1】=0.8*1.8=1.44满意采纳
=3.2×0.2+4×0.2=(3.2+4)×0.2=7.2×0.2=1.44
=4X0.8X0.2十0.8=0.8X(0.8十1)=1.44