Question

How do you solve `9^n + 10 + 3 = 81`?

Answer 1

I would write it as:
`9^n+13=81`
`9^n=81-13=68`
Using the definition of logarithm:
`log_9(68)=n`
I change the base to natural logarithm to evaluate it with a pocket calculator:
`n=log_9(68)=ln(68)/ln(9)=1.92`