假如:2x—3=y;xy=209 请问x=?,y=?
(-3x^y+2xy)-( )=4x^+xy
已知xy=-2,x-y=3,求(x+y)(x-y)-y^2+(x-y)^2-(6x^2y-2xy^2)÷2y
已知3x*+xy-2y*=0,求(x/y)-(y/x)-(x*+y*)/(xy)的值.*是平方
已知3x^2+xy-2y^2=0,求{(x+y)/(x-y)+4xy/(y^2-x^2)}/{(x+3y)*(x-y)}
[-(x-y)^2/xy]^-4*(y^2-xy/x)^3*(x^4/y^10)÷(xy-y^2/x)^-5=-y(y-
已知x-y=4xy,则2x+3xy-2yx-2xy-y
(x+2y-3xy)-(-2x-y+xy),其中x+y=1/2,xy=-1/2
已知x+y分之xy=2,那么3x-5xy+3y分之3xy-x-y=
已知xy/x+y=1/2,则代数式3x-5xy+3y/-x+3xy-y=
若x+y分之xy=2,则-x+3xy-y分之3x-xy+3y=多少?
xy=-2,x+y=3,求代数式(4xy+12y)+[7x-(3xy+4y-x)]
(x+2y-3xy)-(-2x-y+xy),其中x+y=,xy=-,求值.