# How do you express log_2 9 in terms of common logs?

${\log}_{2} 9 = \frac{\log 9}{\log 2}$
Use the change of base formula: ${\log}_{b} x = \frac{\log x}{\log b}$
Therefore, ${\log}_{2} 9 = \frac{\log 9}{\log 2}$