（y-x)3次幂（x-y)n次幂+(x-y）n+1次幂（y-x）2次幂,快一点！！！！！急！！！！！！

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解答判猛判掘改：知烂
[(y-x)^3][(x-y)^n]+[(x-y)^(n+1)][(y-x)^2]
=-(x-y)^(n+3)+(x-y)^(n+3）=0

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