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已知(2011+y-x)(x-y-2009)=-2010,求(2011+y-x)²+(2009+y-x)²的值
人气:316 ℃ 时间:2019-10-17 02:54:08
解答
(2011+y-x)(x-y-2009)=-2010
-(2011+y-x)(2009+y-x)=-2010
(2011+y-x)(2009+y-x)==2010
令a=2011+y-x,b=2009+y-x
所以a-b=2
平方
a²-2ab+b²=4
所以(2011+y-x)²+(2009+y-x)²
=4+2ab
=4+2×2010
=4024
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