若x、y>0.x+y=1.根x+根y

若x、y>0.x+y=1.根x+根y x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 化简 x / y(x+y) - y / x(x+y) = 若(X×X+Y×Y)(X×X+Y×Y-5)=36,则X×X+Y×Y＝ x(x+y)(x-y)-y(y+x)(y-x)=(x-y)( )填空 若D={(X,Y)||X|+|Y| {(x,y) |x|+|y| x>y?x:y x+x+y+y+y=21 ,x+x+y+y+y+y+y=27 ,x ,y=? x+x+y+y+y=21 ,x+x+y+y+y+y+y=27 ,x ,y=? y=x(x 若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值 若X-Y>X,X+Y x+x+x+x+y+y+y=56 x+y=1. 若f(x+y,y/x)=x^2-y^2,则F(X,Y)= 若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于 若x-y=1,求代数式x(x-y)+y(y-x)+2013的值