How do you use the Change of Base Formula and a calculator to evaluate the logarithm #log_15 7#?

1 Answer
Feb 9, 2016

The change of base rule is: #log_an = (logn)/(loga)#


#log_7(15) = (log15)/(log7)#

Now that both logs are in base 10, you can evaluate using a regular scientific calculator by pressing the button labelled "log".

Answer: 1.39

Hopefully this helps!