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计算先化简,再求值:[(x-y)^2+(x+y)(x-y)]÷2x,其中x=3,y=7

题目详情
计算先化简,再求值:[(x-y)^2+(x+y)(x-y)]÷2x,其中x=3,y=7
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答案和解析
[(x-y)²+(x+y)(x-y)]÷2x
=(x-y)(x-y+x+y)÷2x
=2x(x-y)÷2x
=x-y
=3-7
=-4