$\frac{1}{3}(\ln ( - 3) + \ln ( - \frac{1}{3}) = \frac{1}{3}\left( {\ln \left( { - 3 \cdot  - \frac{1}{3}} \right)} \right) = \frac{1}{3}\left( {\ln 1} \right) = \frac{1}{3} \cdot 0 = 0$