八下一道简单的数学题急 急已知x+1\y=y+1\z=1(1)求z+1\x的值;(2)如果实数x.y.z满足x+1\y=4,y+1\z=1,z+1\x=7\3,求xyz的值.(只知道一问就答一问)急 急

八下一道简单的数学题急 急已知x+1\y=y+1\z=1(1)求z+1\x的值;(2)如果实数x.y.z满足x+1\y=4,y+1\z=1,z+1\x=7\3,求xyz的值.(只知道一问就答一问)急 急
八下一道简单的数学题急 急
已知x+1\y=y+1\z=1
(1)求z+1\x的值;
(2)如果实数x.y.z满足x+1\y=4,y+1\z=1,z+1\x=7\3,求xyz的值.
(只知道一问就答一问)
急 急

八下一道简单的数学题急 急已知x+1\y=y+1\z=1(1)求z+1\x的值;(2)如果实数x.y.z满足x+1\y=4,y+1\z=1,z+1\x=7\3,求xyz的值.(只知道一问就答一问)急 急
(1)x=1-1/y,1/x=y/(y-1)
1/z=1-y,z=1/(1-y)=-1/(y-1)
z+1/x=y/(y-1)-1/(y-1)=1
(2)(x+1/y)(y+1/z)(z+1/x)=28/3
(x+1/y)+(y+1/z)+(z+1/x)=22/7
(x+1/y)(y+1/z)(z+1/x)
=xyz+1/(xyz)+(x+1/y)+(y+1/z)+(z+1/x)=28/3
xyz+1/(xyz)=2
(xyz)^2-2(xyz)+1=0
xyz=1