How do you evaluate log_81 27?

1 Answer
George C.
Aug 3, 2016

log_81 27 = 3/4

Explanation:

Using the change of base formula:

log_a b = (log_c b)/(log_c a)

and the definition of logarithm as the inverse of exponentiation:

log_a a^b = b

we find:

log_81 27 = (log_3 27)/(log_3 81) = (log_3 3^3)/(log_3 3^4) = 3/4

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