Solve the Problem $g ( x , y , z )$

Solve the problem.
-For some inexact differential forms df, a function $g ( x , y , z )$ can be found such that dh $= g ( x , y , z ) d f$ is exact. When it exists, the function $g ( x , y , z )$ is called an "integrating factor". Show that $g ( x , y , z ) = \frac { y z } { x }$ is an integrating factor for the inexact differential $\mathrm { df } = - \frac { 1 } { \mathrm { x } } \mathrm { dx } + \frac { 1 } { \mathrm { y } } \mathrm { dy } + \frac { 1 } { \mathrm { z } } \mathrm { dz }$ .