x²-x²y+xy²-x+y-y²,让我看得懂
题目
x²-x²y+xy²-x+y-y²,让我看得懂
答案
x²-x²y+xy²-x+y-y²=(x²-y²)-(x²y-xy²)-(x-y)=(x-y)(x+y)-xy(x-y)-(x-y)=(x-y)(x+y-xy-1)=-(x-y)(xy-x-y+1)=-(x-y)[(xy-x)-(y-1)]=-(x-y)[x(y-1)-(y-1)]=-(x-y)(x-1)(y-1)
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