先化简再求值(2x-3y+5xy)-(x-4y-3xy),其中x+y=-3,xy=-4

分类: 作业答案 • 2022-06-07 15:59:05

问题描述：

答

(2x-3y+5xy)-(x-4y-3xy)
=2x - 3y + 5xy - x + 4y + 3xy
= x + y + 8xy
= -3 + 8*(-4)
= -35

答

(2x-3y+5xy)-(x-4y-3xy)
＝x+y+8xy
=-3-8x4
=-35

答

(2x-3y+5xy)-(x-4y-3xy)
=2x-3y+5xy-x+4y+3xy
=2x-x-3y+4y+5xy+3xy
=x+y+8xy
=(x+y)+8(xy)
=-3+8*(-4)
=-3-32
=-35