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已知xy=2,x-y=3,求(x+y)(x-y)-y^2-(6x^2y-2xy^2)/2y的值.
人气:122 ℃ 时间:2020-03-26 13:51:59
解答
(x+y)(x-y)-y^2-(6x^2y-2xy^2)/2y
=x^2-y^2-y^2-3x^2+xy
=-2(x^2+Y^2)+xy
=-2(x^2+Y^2-2xy)-4xy+xy
=-2(x-y)^2-3xy
=-2*3^2-3*2
=-24
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