已知三个数x,y,z满足

已知三个数x,y,z满足
已知三个数x,y,z满足

已知三个数x,y,z满足
xy/(x+y)=-2
(x+y)/xy=-1/2
1/y+1/x=-1/2
yz/(y+z)=4/3
(y+z)/yz=3/4
1/z+1/y=3/4
zx/(z+x)=-4/3
(z+x)/zx=-3/4
1/x+1/z=-3/4
1/x+1/y+1/z=yz/xyz+xz/xyz+xy/xyz
=(yz+xz+xy)/xyz
=1/2(-1/2+3/4-3/4)
=-1/4
xyz/(xy+yz+zx)=-4