Posted by molly on .
evaluate 15^(2log base15(9))

algebra 
Steve,
15^(log_{15}n) = n
That's the definition of the logarithm. It's the power of the base needed to get the number.
So, 15^log9 = 9 (using base 15)
15^2log9 = (15^log9)^2 = 9^2 = 81