已知x+y=1,xy=-2,则x²y+xy²-2xy

已知(x+1)²+|y-1|=0,求2(xy-5xy²)-(3xy²-xy)得值 已知x:y=3:2,求(x²+3xy)/(xy+2xy) 已知实数xy满足x²﹢y²-xy+2x-y+1=0求xy 已知xy/x+y=1/2,则代数式3x-5xy+3y/-x+3xy-y= 已知x-y=4xy，则2x+3xy-2yx-2xy-y 已知：xy+x=-1，xy-y=-2． 已知x²-3xy+4x=3,y²+xy-4y+7=0,则xy-1/2(x²+y² 已知x/y=3,求(x²+2xy-3xy²)/(x²-xy+y²) 已知X/Y=2,则X²+2XY-3Y²/X²-XY+Y²=? 已知X²+Y²+X²Y²-4XY+1=0 求:（X-Y)^2008-(XY)^2 已知x+y=2,xy=1/2,求x³y+2x²y²+xy³ X²+2xy+y²/xy乘x²-2xy+y²/xy+y²=