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先化简再求值
(-2xy+2x+3y)-(3xy+2x-2y)-(x+4y-xy),其中x、y满足x-y=10,xy=-4
人气:292 ℃ 时间:2019-08-31 14:22:29
解答
(-2xy+2x+3y)-(3xy+2x-2y)-(x+4y-xy)
=-2xy+2x+3y-3xy-2x+2y-x-4y+xy
=-4xy-x+y
=-4xy-(x-y)
=-4×(-4)-10
=6
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