已知:x(x-50y)+xy=50y^2,求:(x-y):y=?
已知x*x-4xy+4y*y=0 求[2x(x+y)-y(x+y)]/(4x*x-4xy+y*y)的值?
已知x/y=2,求2x(x+y)-y(x+y)/4x²-4xy+y²
已知xy=-2,x-y=3,求(x+y)(x-y)-y^2+(x-y)^2-(6x^2y-2xy^2)÷2y
已知x+y=-1,xy=-2,求代数式-5(x+y)+(x-y)+x(xy+y)的值
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)}
已知x-3y=0,求(2x+y)/(x^2-2xy+y^2)X(x-y)
已知xy=-2,x-y=3,求(x+y)(x-y)-y²+(x-y)²-(6x²y-2xy
已知x,y∈R*,x+y=xy,求u=x+2y最小值
已知二元函数f(xy,x+y)=x^2+y^2,求f(x,y)
已知x平方-y平方=2xy 求x+y分之x-y
已知x,y>0 2x+y+3=xy 求5x+4y最小值