Question 882228
Choose use of Change of Base Formula, because we do not typically have tabulated information about logs to base 7.



Choosing Common Logs, base ten:

{{{log(7,9)=log((9))/log((7))}}}   and  {{{log(7,4)=log((4))/log((7))}}}.


{{{k=(log((9))/log((7)))/(log((4))/log((7)))}}}


{{{highlight(k=log((9))/log((4)))}}}.


You can use a table of common logarithms or an electronic calculator for {{{log((9))=0.954243}}}  and {{{log((4))=0.60206}}}
{{{k=(0.954243)/(0.60206)=1.5850}}}