7y+120=5xy=?x=?x+y=?
已知x-y=3xy,且xy不等于0,则-3x+6xy+3y/(7x-5y)-9xy-(3x-y)
已知xy^2=-2求xy(2x^3y^7+5x^2y
已知x+y=-1,xy=-2,求代数式-5(x+y)+(x-y)+x(xy+y)的值
已知实数x,y,xy=5,x+y=7,求代数式x²y+xy²的值
x分之一减y分之一等于7,则x-3xy-Y分之3x+5xy-3y=?
已知1/x-1/y=5 求分式-x+xy+y/2x+7xy-2y
已知1/x-1/y=5,求分式y+xy-x/2x+7xy-2y的值.
已知1/X-1/y=5,求分式(y+xy-x)/(2x+7xy-2y)的值
1/x-1/y=5求(-x+xy+y)/(2x+7xy-2y)
已知x+y=-5,x*x+y*y=19求xy和(x-y)*(x-y)的值
[-(x-y)^2/xy]^-4*(y^2-xy/x)^3*(x^4/y^10)÷(xy-y^2/x)^-5=-y(y-
解方程x*x+xy=y+y*y