问题 填空题

分解因式:x2-2x-y2+2y=______.

答案

x2-2x-y2+2y=(x2-y2)-(2x-2y)=(x+y)(x-y)-2(x-y)=(x-y)(x+y-2).

故答案为:(x-y)(x+y-2).

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