已知x+15=y+12=z+5,求x^2+y^2+z^2-xy-xz-yz
已知X+Y+Z=2XY+YZ+XZ=-5求X^2+T^2+Z^2
已知4x-5y+2z=0,x+4y-3z=0,求(x²+y²+z²)/xy+yz+xz
已知2/x=3/y=7/z,求xy+xz+yz/x^2+y^2+z^2
已知x+y+z=1,xy+yz+xz=0,求x^2+y^2+z^2的值.
已知x^2+y^2+z^2-xy-yz-xz=0,求x,y,z 的大小关系
已知x+y+z=1,x²+y²+z²=2求xy+yz+xz的值
(2X+Z-Y)/(X^2-XY+XZ-YZ)-(Y-Z)/(X^2-XY-XZ+YZ)
已知x+y+z=5,xy+yz+xz=7,则x^2+y^2+z^2等于?
求(2X+Z-Y)/(X^2-XY+XZ-YZ)-(2X+Y+Z)/(X^2+XY+XZ+YZ)
x/3=y/2=z/5,求xy+yz+xz/x²+y²+z²
已知x-y=5,y-z=2,求x2+y2+z2-xy-yz-xz的值
已知x+y+z=3,xy+yz+xz=-1,xyz=2,求x^2y^2+y^2z^2+x^2z^2