xy=-9,x+y=3,求x,y
已知x+y=12,xy=9,求(x+3xy+y)/(xy+xy)的值
y'+xy=x^3求微分
已知3x*+xy-2y*=0,求(x/y)-(y/x)-(x*+y*)/(xy)的值.*是平方
x>1,y>0,且满足xy=x^y,x/y=x^3y,求x+y
已知x-xy=8,xy-y=-9,求x+y-2xy的值
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^2+xy-2y^2=0,求{(x+y)/(x-y)+4xy/(y^2-x^2)}/{(x+3y)*(x-y)}
xy=-2,x+y=3,求代数式(4xy+12y)+[7x-(3xy+4y-x)]
已知,xy/x+y=3,求代数式3x-5xy+3y/-x+3xy-y的值
已知xy/x+y=3,求代数式3x-5xy+3y/-x+3xy-y的值.
已知XY.Y=-3,求-XY(X.X.X.Y.Y.Y.Y.Y.Y.Y-3.X.X.Y.Y.Y.Y.Y-Y)的值.(过程完
已知X+Y分之XY=2,求-X+3XY-Y分之3X+5XY+3Y