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幼苗
共回答了19个问题采纳率:84.2% 举报
xx是指x^2吧!
如果是{(x+y)(x-y)-(x-y)^2+2y(x^2-3y)}÷(-4y)的话,原式=(x^2-y^2-x^2+2xy-y^2+2x^2y-6y^2)÷(-4y)=(2x^2y+2xy-8y^2)÷(-4y)=2y-x/2-x^2/2
如果是{(x+y)(x-y)-(x-y)^2+2y(x-3y)}÷(-4y)的话,原式=(x^2-y^2-x^2+2xy-y^2+2xy-6y^2)÷(-4y)=(4xy-8y^2)÷(-4y)=2y-x
1年前
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