X+Y=2 XY=3 求 2【XY+（-3x）】-3(2Y-XY)的值

来源：学生作业帮编辑：作业帮分类：数学作业时间：2024/05/10 14:48:09

X+Y=2 XY=3 求 2【XY+（-3x）】-3(2Y-XY)的值
我做了一半了,2【XY+（-3x）】-3(2Y-XY)=2XY-6X-6Y=3xy=5xy-6x-6y

解
2[xy+(-3x)]-3(2y-xy)
=2xy-6x-6y+3xy
=5xy-6(x+y)
=5×3-6×2
=15-12
=3
再问： X,Y的值怎么求？其余的我都会，给讲一下吧！ ~(@^_^@)~
再答：不用求，5xy中xy=3 -6(x+y)中x+y=2 都直接代入就可以了

已知xy^2=-2,求-xy（x^2y^5-xy^3-y)的值. 已知x-y=4，xy=-2，求代数式(2x+3y-2xy)-(x+4+xy)-（3xy+2y-2x）的值已知xy/x+y =3,求2x-3xy+2y/-x+3xy-y 的值. 已知xy/x+y=3,求2x-3xy+2y/-x+3xy-y的值若(y-x)/xy=3,求分式(2x+3xy-2y)/(x-2xy-y)的值已知x-y/xy=3,求分式2x+3xy-2y/x-2xy-y的值. 已知3x=xy+3y,求2x+xy-2y/y-x-xy的值已知xy/x+y=2,求代数式3x-5xy+3y/-x+2xy-y的值已知xy/x+y=2,求代数式3x-xy+3y/-x+3xy-y的值已知xy/x+y=6,求3x-2xy+3y/-x+3xy-y的值. 已知X+Y=3XY,求2X+2Y-XY除以X+Y+2XY的值,要算理. 已知x-y=4xy,求x-2xy-y分之2x+3xy-2y的值!