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_数学解答

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：407 ℃　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