4x²y-1/2{x²y-[5x²y-2(2xy²+1/4xy)]}+3xy&#

4x²y-1/2{x²y-[5x²y-2(2xy²+1/4xy)]}+3xy²,其中x=2,y=-3
陈子霄 1年前 已收到2个回答 举报

地_下铁 幼苗

共回答了21个问题采纳率:100% 举报

4x²y-1/2{x²y-[5x²y-2(2xy²+1/4xy)]}+3xy²
=4x²y-1/2{x²y-[5x²y-4xy²-1/2xy]}+3xy²
=4x²y-1/2{x²y-5x²y+4xy²+1/2xy}+3xy²
=4x²y-1/2{-4x²y-4xy²-1/2xy}+3xy²
=4x²y+2x²y+2xy²+1/4xy+3xy²
=6x²y+5xy²+1/4xy
=xy(6x+5y+1/4)
=-2×3×(6×2-5×3+1/4)
=-6×(-11/4)
=16.5

1年前

2

crystal007 幼苗

共回答了17个问题采纳率:82.4% 举报

很好啊

1年前

2
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