How to solve 3^x = 2187 by using Casio fx-85GT plus

Question

I need to solve 3^x = 2187 by using Casio fx-85GT plus and I couldn't find anything in its manual.

I know how to do it manually and the answer is "x = 7". But how can I do it using the calculator. Please advise, many thanks!!

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Regards,

Answer 1

As requested in the comments:

Taking $\log$ helps. We see $$x\times \log 3 = \log 2187\implies x= \frac {\log 2187}{\log 3}$$

Here I intend the natural log, but any base would work. Using any sort of calculator one then gets $x=7$.

Note: it is easy to verify that $3^7=2187$ which confirms the result.