# How do you express log_2 13 in terms of common logarithms?

${\log}_{2} \left(13\right) = {\log}_{10} \frac{13}{\log} _ 10 \left(2\right) = \ln \frac{13}{\ln} \left(2\right)$
${\log}_{c} \left(a\right) = {\log}_{b} \frac{a}{\log} _ b \left(c\right)$