已知x-y=1,则x^4-x^3y-xy^3-3x^2y+3xy^2+y^4=
已知x-y=4xy,则2x+3xy-2yx-2xy-y
已知:x-y=1,xy=-2.求:(-2xy+2x+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=3,xy=1,求(-2x+2x+3y)-(3xy+2y-2x)-(x+4y+xy)
已知3x^2+xy-2y^2=0,求{(x+y)/(x-y)+4xy/(y^2-x^2)}/{(x+3y)*(x-y)}
已知xy/x+y=1/2,则代数式3x-5xy+3y/-x+3xy-y=
已知x-y=4xy,求x-2xy-y分之2x+3xy-2y的值!
已知1/x-1/y=3,求(3x+4xy-3y)/(x-2xy-y)的值
已知1/x+1/y=3,求3x-4xy+3y/(x+2xy+y)的值
已知x,y>0 2x+y+3=xy 求5x+4y最小值
已知x-y=1,则x^4-x^3y-xy^3-3x^2y+3xy^2+y^4=
若x+y=-1,则x^4+5x^3y+x^2y+8x^2y^2+xy^2+5xy^3+y^4=( )