问题 解答题

先化简,再求值:[(x-y)2+(x+y)(x-y)]÷2x,其中x=2005,y=2004.

答案

[(x-y)2+(x+y)(x-y)]÷2x,

=(x2-2xy+y2+x2-y2)÷2x,

=(2x2-2xy)÷2x,

=x-y,

当x=2005,y=2004时,原式=2005-2004=1.

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