Chapter 4 - Inverse, Exponential, and Logarithmic Functions - 4.4 Evaluation Logarithms and the Change-of-Base Theorem - 4.4 Exercises - Page 456: 23

$3.9494$

Apply logarithmic property : $\log m+ \log n=\log (mn)$ $\log 387+ \log 23=\log (387 \times 23) = \log 8901$ Now, take logarithmic to the base $10$ and evaluate the result. Therefore, our answer is: $\log_{10} 8901 \approx 3.9494$