# How do you use the Change of Base Formula and a calculator to evaluate the logarithm log_7 28?

Nov 10, 2015

${\log}_{7} 28 = \frac{\log 28}{\log 7} = 1 , 7124$
${\log}_{a} b = \frac{{\log}_{c} b}{{\log}_{c} a}$
So therefore ${\log}_{7} 28 = \frac{\log 28}{\log 7} = 1 , 7124$