To rewrite \( \log(1/81) \) with a negative exponent, we can express \( \frac{1}{81} \) as \( 81^{-1} \):
\[ \log\left(\frac{1}{81}\right) = \log(81^{-1}) \]
Now, using the Power Rule of Logarithms, which states that \( \log(a^b) = b \cdot \log(a) \), we can simplify:
\[ \log(81^{-1}) = -1 \cdot \log(81) = -\log(81) \]
So, we have:
\[ \log\left(\frac{1}{81}\right) = -\log(81) \]