已知x-y=6,xy=-2,求3（xy+x-2y）-5(y-2x)+2(xy-x)的值.RT.答对加悬赏.
问题描述：
已知x-y=6,xy=-2,求3（xy+x-2y）-5(y-2x)+2(xy-x)的值.
RT.答对加悬赏.
答
56,你把xy等于负二代入,,展开的十一倍X减Y减十,得五十六。
答
x-y=6
xy=-2
3(xy+x-2y)-5(y-2x)+2(xy-x)
=3xy+3x-6y-5y+10x+2xy-2x
=5xy+11x-11y
=11(x-y)-10
=11*6-10
=56
答
已知x-y=6,xy=-2,
求3（xy+x-2y）-5(y-2x)+2(xy-x)的值.
=3xy+3x-6y-5y+10x+2xy-2x
=5xy+11x-11y
=5×(-2)+11×6
=-10+66
=56;
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答
答：
x-y=6，xy=-2
3(xy+x-2y)-5(y-2x)+2(xy-x)
=3xy+3x-6y-5y+10x+2xy-2x
=11x-11y+5xy
=11(x-y)+5xy
=11*6+5*(-2)
=66-10
=56