先化简再求值:x^3-xy^2-x(x+y)^2,其中x+y=2,xy=1/2
人气:265 ℃ 时间:2020-04-09 01:21:39
解答
x^3-xy^2-x(x+y)^2
=x^3-xy^2-x(x^2+2xy+y^2)
=x^3-xy^2-x^3-2x^2y-xy^2
=-2x^2y-2xy^2
=-2xy(x+y)
=-2*1/2*2
=-2
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