Question

evaluate 15^(2log base15(9))

Answer 1

15^(log₁₅n) = 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