pig830809
幼苗
共回答了16个问题采纳率:87.5% 举报
1.(2x-3y)^2=( 4x^2-12xy+9y^2 )
2.(1/4a+2/5b)^2=( 1/6a^2+1/5ab+4/25b^2 )
3.用完全平方公式计算197^2=( 200-3 )^2=( 40000-1200+9 )=(38809 )
4.-4xy^2÷(-xy)=( 4y ),15m^2÷5m^2=( 3 )
5.A÷2ab^2=-1/3a^2b,则A=( -2/3a^3b^3 )
6.若(-7m+A)(4n+B)=16n^2-49m^2,则A=(4n ),B=( 7m )
1年前
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