College Algebra, Chapter 5, 5.3, Section 5.3, Problem 12

Evaluate the expression $\displaystyle \log_{12} 9 + \log_{12} 16$


$
\begin{equation}
\begin{aligned}

\log_{12} 9 + \log_{12} 16 =& \log_{12} (9 \cdot 16)
&& \text{Law of Logarithm } \log_a (AB) = \log_a A + \log_a B
\\
\\
\log_{12} 9 + \log_{12} 16 =& \log_{12} (144)
&& \text{Simplify}
\\
\\
\log_{12} 9 + \log_{12} 16 =& 2
&& \text{Because } 12^2 = 144

\end{aligned}
\end{equation}
$