題目不完整呀? 設(shè)：甲乙兩件服裝成本分別是xy元x+y=500[x(1+50%)+y(1+40%)]*0.9-(x+y)=157(1.5x+1.4y)*0.9-500=1571.35x+1.26y=657將x+y=500變形為x=500-y代入上式675-1.35y+1.26y=6570.09y=18y=200(乙成本）x=500...一元一次方程哦設(shè)：甲服裝成本分別是x500-x元[x(1+50%)+(500-x)(1+40%)]*0.9-500=157(1.5x+700-1.4x)*0.9-500=157(0.1x+700)*0.9=6570.09x+630=6570.09x=27x=300（甲成本）則乙服裝成本＝500-300＝200甲乙兩件服裝成本分別是300元和200元