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
问题描述：
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
答
[(xy+2)(xy-2)-2(x²y²-2)]÷xy
=[x²y²-2²-2x²y²+4]÷xy
=(-x²y²)÷xy
=-xy
当x=2013,y=1/2013时
原式=-2013×(1/2013)
=-1
答
(xy+2)(xy-2)-2(x²y²-2)
=x²y²-4-2x²y²+4
= - x²y²
[(xy+2)(xy-2)-2(x²y²-2)]÷xy
=-xy= - 2013*(1/2013)=-1
答
解
[(xy+2)(xy-2)-2(x²y²-2)]÷xy
=[x²y²-4-2x²y²+4]÷xy
=(-x²y²)÷xy
=-xy
=-2013×(1/2013)
=-1