先化简在求值, 不会做的不要来 [(xy+2)(xy-2)-2(x²y²-2)]÷xy,其中x=20
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先化简在求值, 不会做的不要来 [(xy+2)(xy-2)-2(x²y²-2)]÷xy,其中x=2013,y=1/2013
![先化简在求值, 不会做的不要来 [(xy+2)(xy-2)-2(x²y²-2)]÷xy,其中x=20](/uploads/image/z/18617788-28-8.jpg?t=%E5%85%88%E5%8C%96%E7%AE%80%E5%9C%A8%E6%B1%82%E5%80%BC%2C+%E4%B8%8D%E4%BC%9A%E5%81%9A%E7%9A%84%E4%B8%8D%E8%A6%81%E6%9D%A5+%5B%28xy%2B2%29%28xy-2%29-2%28x%26%23178%3By%26%23178%3B-2%29%5D%C3%B7xy%2C%E5%85%B6%E4%B8%ADx%3D20)
解
[(xy+2)(xy-2)-2(x²y²-2)]÷xy
=[x²y²-4-2x²y²+4]÷xy
=(-x²y²)÷xy
=-xy
=-2013×(1/2013)
=-1
[(xy+2)(xy-2)-2(x²y²-2)]÷xy
=[x²y²-4-2x²y²+4]÷xy
=(-x²y²)÷xy
=-xy
=-2013×(1/2013)
=-1
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