令x/3=y/1=z/2=kx=3ky=kz=2kxy+yz+zx=993k*k+k*2k+3k*2k=993k^2+2k^2+6k^2=9911k^2=99k^2=9k=±3x^2=9k^2=9*9=81y^2=k^2=9z^2=4k^2=4*9=36当k=3时,z=6zx^2+9y^2+9z^2=6*81+9*9+9*36=891当k=3时,z=-6zx^2+9y^2+9z^2=-...