x=y且xy≠0.求1910x^2+99y^2/2009xy

x=y且xy≠0.求1910x^2+99y^2/2009xy 已知xy≠0,且2x+3xy-2y=0,求(x+y)/(x-y)的值. 已知x-y=4xy且xy≠0,求代数式-x-2xy+y分之2x+3xy-2y的值 已知x²-y²=xy,.且xy≠0.求代数式x²y的-2次方＋x的-2次方y²的值 已知x>0,y>0,且x+2y+xy=30,求xy的最大值 已知X>0,Y>0且X+2Y+XY=30求XY最大值 已知xy≠0,且3x^2-2xy-8y^2=0,求x/y的值? 已知,xy≠0,且3x²-2xy-8y²=0,求x/y的值 已知xy≠0,且3x²-2xy-8y²=0,求x/y的值 xy≠0且3x^-2xy-8y=0求x/y的值 xy≠0且3x^-2xy-8y=0求x/y的值 已知x²-xy-y²=0,且x≠0,y≠0.求代数式（x²-2xy-5y²）/（x²+2xy+5y²）的值 x,y为正整数,且x^2-xy-2y^2=7,求x,y x,y为正整数,且x^2-xy-2y^2=7,求x,y 已知x.y为正实数,且2x+8y-xy=0.求x+y的最小值, 若x,y为实数,且|x-2|+√(y-2)=0.求代数式(x-y)/x除以(x-(2xy-y^2)/x)的值 若x^2+y^2-2xy=49,且x>y,x+y=9,求xy的值 已知x-7y=0,且y≠0,求2x²﹢xy-3y²分之x²-3xy+y²的值