若xyz=1,求 x/(xy+x+1) +y/(yz+y+z) +z/(zx+z+1)

分解因式：xyz-yz-zx-xy+x+y+z-1 xy+yz+zx=1,求x√yz+y√zx+z√xy xy+yz+zx=1,x,y,z>=0 已知x,y,z都是正数,且xyz=1,求证：xy(x+y)+yz(y+z)+zx(z+x)》6 (1/x+1/y+1/z)×(xy)/(xy+yz+zx) 已知xyz=1，x+y+z=2，x2+y2+z2=16，求代数式1xy+2z+1yz+2x+1zx+2y 设xyz=1,求x/（xy+x+1）+y/（yz+y+1）+z/（zx+z+1）的值 已知2x+2y+xy=-2,2y+2z+yz=-1,2z+2x+zx=50,求xyz+2(xy+yz+zx)+4(x+y 1.x,y,z为实数,且xy/x+y=1/3,yz/y+z=1/4,xz/x+z=1/5,求xyz/xy+yz+zx的值 x,y,z为实数,且xy/x+y=1/3,yz/y+z=1/4,xz/x+z=1/5,求xyz/xy+yz+zx的值 急!x,y,z为实数,且xy/x+y=1/3,yz/y+z=1/4,xz/x+z=1/5,求xyz/xy+yz+zx的值 已知xy：yz：zx=3：2：1,求①x:y:z ②x/yz:y/zx