已知|x-1/x-9 - y-1/y+15|+|x+6/x+9 - y-3/y|=0 求12y2-490/x

已知y/x=9/10则(1-y/x)[x/(y-x)]? 已知x平方-6x+9与/y-1/互为相反数,计算(x/y-y/x)÷( x+y) 已知x,y满足{x>=1,x+y 已知x,y满足{x>=1,x+y 已知x>0,y>0,x+9y=1求x+y的最小值? 已知x>0y>01/x+9/y=1,求证：x+y>=16.快 已知x+y=a,2x-y=-2a,求[（x/y-y/x)/(x+y)-x(1/x-1/y)]/[(x+1)/y]的值 已知4x=9y求(1)x+y/y (2)y-x/2x有关比例的 已知x>0,y>0 x+y+9/x+1/y=10,则x+y则最大值为? 已知正实数x,y满足x+y+1/x+9/y=10,则x+y的最大值是 已知x×x×y×y+x×x+y×y+1=4xy,求x,y的值快 已知x,y是整数,且x(x-y)+2012y(x-y)=1,求x,y的值. 已知 x/(y+z)+y/(z+x)+z/(x+y)=1求 (x*x)/(y+z)+(y*y)/(x+z)+(z*z)/(x+y)=? 已知函数Y=-x+1,(x 已知x+y=1,xy=-二分之一,求x（x+y)(x-y)-x(x+y)² 已知x+y=1,xy=-二分之一,求x（x+y)(x-y)-x(x+y)² 已知:【(x²+y²)-(x-y)²+2y(x-y)】/4y=1,求4x/4x²-y²-1/2x+y 已知x-y=1,求[(x+2y)²+(2x+y)(x-4y)-3(x+y)(x-y)]÷y的值