## Precalculus (6th Edition) Blitzer

The solution of the giving expression is $x=9$.
It is given that ${{\log }_{2}}\left( \frac{x+9}{x} \right)=1$ \begin{align} & \log \left( \frac{x+9}{x} \right)=\log \,2 \\ & \frac{x+9}{x}=2 \\ & x+9=2x \\ & x=9 \end{align} Therefore, the solution of the giving expression is $x=9$.