y=-x-1〉y=-2/x,求X的取值范围

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 若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值 若x*x+y*y=x+y-1/2,求x,y的值如题 已知x-y=1,求[(x+2y)^2+(2x+y)(x-4y)-3(x+y)(x-y)]除以y的值大神们帮帮忙 已知x-y=1,求[(x+2y)²+(2x+y)(x-4y)-3(x+y)(x-y)]÷y的值 已知x-y=3,求[（x+y)(x-y)-(x-y)^2+2y(x-y)]除以的值 y=(1+x^2)的x次方,求y ' 求y‘-(1/x)y=x^2 的通解 y=3(x-y),x=2(x-y)求x,y的值 已知x≠y,x^2-x=y^2-y,求x+y的值. 若x-y=1,求代数式x(x-y)+y(y-x)+2013的值 x,y 满足x(x-2)-y(y-6)=-10,求x,y的值 正数x,y满足x-y=2xy,求x-y/x+y的值. 当x=-1 y=-2时求代数式[2x^2-(x+y)(x-y)][(-x-y)(-x+y)+2y^2]的值 1奥数题x-2y/x+2y=3,求x-2y/3(x+2y)-3(x-2y)/x-2y的差 若|x+y-1|+（x-y-2)²=0,求代数式（x+2y)(x-2y）-（2x-y)(-y-2x)的值. 当x+y/x-y=1/2时,求代数式x-y/x+y-2x+2y/x-y的值 当x-y/x+y= -1/2时,求y-x/x+y -2x+2y/x-y的值.（要有过程)