y设(y+z)/x=(z+x)/y=(x+y)/z=k
(y+z)=kx
(z+x)=ky
(x+y)=kz
(y+z)+(z+x)+(x+y)=kx+ky+kz
2(x+y+z)=k(x+y+z)
k=2
xyz分之(y+z)(z+x)(x+y)
=2x*2y*2z/xyz
=8xyz/xyz
=8
y设(y+z)/x=(z+x)/y=(x+y)/z=k
(y+z)=kx
(z+x)=ky
(x+y)=kz
(y+z)+(z+x)+(x+y)=kx+ky+kz
2(x+y+z)=k(x+y+z)
k=2
xyz分之(y+z)(z+x)(x+y)
=2x*2y*2z/xyz
=8xyz/xyz
=8