.已知:x-y=1,xy=-2.求:(-2xy+2 x+3y)-(3xy+2y-2x)-(x+4y+xy)的值

.已知:x-y=1,xy=-2.求:(-2xy+2 x+3y)-(3xy+2y-2x)-(x+4y+xy)的值 (已知:x+y=1/2.xy=1,求x³y+2x²y²+xy³ 已知3/(x-y)=1/xy 求(-x-2xy+y)/ (2x+3xy-2y) 已知xy-x-y=11,求(xy-1)^2+(x+y-2)(x+y-2xy)的值. 已知x+y=-1,xy=-2,求代数式-5（x+y)+(x-y)+x(xy+y)的值 已知|x+y+1|+|xy+3|=0,求代数式xy^3+X^3y 已知X、Y属于R+,且XY-(X+Y)=1,求XY的范围 已知XY为正数,X+Y=1 求1/XY+XY的最小值 已知x y=1,xy=-3,求2xy-4x 4(y-2(xy-x)) 已知x+y=-1,xy=-2,求代数式-5（x+y)+(x-y)+2(xy+y)的值 1.已知x+y=-4,xy=3,求5（2分之1xy+2y）+[6x-(2xy+y-3x)]的值2.已知（x+3）^2+|x-y+10|=0求代数式5x^2y-[2x^2y-(3xy-xy^2)-3x^2]-2xy^2-y^2的值 已知x(x-1)-(x²-y)=-3,求(x²y+xy²)÷xy-2y 已知x²+xy=2,xy+y²=1,求x²+2xy+y²的值 已知实数xy满足x²﹢y²-xy+2x-y+1=0求xy 已知x-xy=8,xy-y=-9,求x+y-2xy的值 【数学】已知 1/x-1/y=3 求 5x-xy-5y / x-2xy-y=?已知 1/x=1/y 求 2x-3xy-2y / x-2xy-y=? 已知1/x-1/y=2001,求分式x-xy-y/x-y的值 已知x>y>0,xy=1,求x^2+y^2/x-y的最小值.