若x^2+xy-2y^2=0,则(x^2+3xy+y^2)/(x^2+y^2)=多少
若x+y分之xy=2,则-x+3xy-y分之3x-xy+3y=多少?
由已知x+y=-2,xy=3那么2(x+xy)-[(xy-3y)-x]-(-xy)等于多少?
若x+y-5xy=0,求(2x-3xy+2y)/(x+2xy+y)的值
{x,xy,lg(xy)}={0,|x|,y} 则log8(X^2+Y^2)
已知x-y=4xy,则2x+3xy-2yx-2xy-y
已知3x*+xy-2y*=0,求(x/y)-(y/x)-(x*+y*)/(xy)的值.*是平方
若(y-x)/xy=3,求分式(2x+3xy-2y)/(x-2xy-y)的值
若y-x/xy=3,求分式2x+3xy-2y/x-2xy-y
(-3x^y+2xy)-( )=4x^+xy
(x+2y-3xy)-(-2x-y+xy),其中x+y=,xy=-,求值.
已知xy/x+y=1/2,则代数式3x-5xy+3y/-x+3xy-y=
(xy-x^2)乘以(xy)/(x-y)