已知2/x=3/y=4/z,求4x²+2yz+z²/x+y+z×x-y-z/8x²+4yz

已知3x-4y-z=0 2x+y-8z =0,求(x²+y²-z²)/(xy+yz)的值 已知4x-5y+2z=0,x+4y-3z=0,求(x²+y²+z²)/xy+yz+xz 已知4x-3y-3z=0,x-3y-z=0 求xy+2yz/x²+y²+z² 已知三个数x,y,z,满足xy/x+y=-2，yz/y+z=4/3,zx/z+x=-4/3,求(xyz)/(xy+yz+ 已知x/3=y/4=z/6,求（xy+yz+xz)/（x²+y²+z²） 1.已知3x-4y-z=0,2x+y-8z=0.求x²+y²+z²/xy+yz+2xz 的 已知3x-4y-z=0,2x+y-8z=0,求xy+yz分之x二次方+y二次方-z二次方 已知x-y=4,y-z=2,求x^2y+y^2z+z^2x-(xy^2+yz^2+zx^2)的值 已知x-y=4,y-z=2,求x^2y+y^2z+z^2x-(xy^2+yz^2+zx^2)的值. 已知x/2=y/3=z/4,求x²+2y²+3z²/xy+yz-zx 已知x+y+z=1,x²+y²+z²=2求xy+yz+xz的值 已知x+y+z=2,xy+yz+zx=-5,求x²+y²+z²的值