已知3/x+y=4/x+y=5/y+z,求xyz/（x+y）（y+z)(z+x)的值

如果是3/(x+y)=4/(x+z)=5/(y+z),设为=k,则x+y=3/k,x+z=4/k,y+z=5/k,那么x=1/k,y=2/k,z=3/k,所以xyz/[（x+y)(y+z)(z+x)]=1/10,如果是这样的话.--------------------------------------------------------------------...