1.-15=xy+y(y-1)/2*2-15=y(x+1)/22.57/5=x(1-y^3)/1-y57/5=x-27/5*y/1-y" /"都是分号的意思!“^3“是三次方1.-15=[xy+y(y-1)/2]×2-15=y(x+1)/22.57/5=x(1-y^3)/(1-y)57/5=x-27/5×y/(1-y)

化简求值1.x^2+2xy+y^2/x^2-y^2除以x^2+xy/xy-y^2X=1Y=-2011 1.（xy-1）^2-(x+y-2xy)(2-x-y)2.(x+y)(x+y+2xy)+(xy-1)(xy+1) 若1/x-1/y=2,求3x-2xy-3y/x-xy-y的值3x-2xy-3y/x-xy-y 不好意思，是3x-2xy-3y/x-2xy-y 已知x+y=1,xy=-2,则x²y+xy²-2xy xy^2-e^x+e^y=1 求y' 是xy^2 不是xy 1-2/x+y=xy,4y+6x=xy.求xy的解? xy'+y=-xy^2的通解 x-2y=15,xy=-25,求x*x+4y*y-1 先化简,在求值1.x²－（x²＋2xy－y²)＋5(y²－3xy),其中x=1/17,y=1/3﹙2﹚5xy－[x²＋2xy－2y²﹚],其中x=﹣2,y=﹣15xy－[x²＋4xy－y²-（x²+2xy-2y²﹚],其中x=﹣2,y=﹣1 3X^2+XY+Y=15 求XY. ( )-(x^2+3xy)=-xy-1/3y^2 （x+2y-3xy)-(-2x-y+xy),其中x+y=1/2,xy=-1/2 因式分解（x+y-2xy)(x+y-2)+(xy-1)^2设x+y=a,xy=b, 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. .(x+y-2)(x+y-2xy)+(xy-1)^2 已知xy/x+y=1/2,则代数式3x-5xy+3y/-x+3xy-y= x+y=1,xy=-2求(x²+y²+xy)/(x²+y²-xy)