∵x+

1

y

=z+

1

x

=1，

∴

1

y

=1-x，z=1-

1

x

=

x-1

x

，

∴y=

1

1-x

，

1

z

=

x

x-1

，

∴y+

1

z

=

1

1-x

+

x

x-1

=

1-x

1-x

=1．