The change of base formula allows you to write a logarithm in terms of logarithms with another base. It follows this pattern,
[tex] log_{a}x = \frac{ log_{b}x }{log_{b}a } [/tex]
where a≠1 and b≠1
Assigning the base to be 7,
[tex]log_{3}73 = \frac{ log_{7}73 }{log_{7}3 }=3.9[/tex]
I hope I was able to answer your question. Have a good day.
