已知,x-y=2,xy=7 求x^2 y-xy^2
已知x-xy=8,xy-y=-9,求x+y-2xy的值
已知xy^2=-2求xy(2x^3y^7+5x^2y
已知X+y=6,xy=7 求x^2y+xy^2=
已知x=3y,试求(x-y)^2+2xy-y^2/x^2+7xy+y^2
已知xy^2=-2,求-xy(x^2y^5-xy^3-y)的值.
已知xy^2=-2 求-xy(x^2y^5-xy^3-y)
已知x^2-xy=5,xy-y^2=-3求3(x^2-xy)-xy+y^2
已知X+Y=3XY,求2X+2Y-XY除以X+Y+2XY的值,要算理.
已知x-y=4xy,求x-2xy-y分之2x+3xy-2y的值!
已知x+y=3xy,求2x+2y-xy/x+y+2xy的值、
已知3/(x-y)=1/xy 求(-x-2xy+y)/ (2x+3xy-2y)
已知x-y/xy=3,求分式2x+3xy-2y/x-2xy-y的值.