The easiest way is to write down a sequence of all the powers of your bases, which you can get by continually multiplying by the base... Then it's position tells you what the power is...

E.g. powers of 2 are 2, 4, 8, 16, 32, 64, etc... (which we get by continually multiplying by 2).

Since 32 is in the 5th position, .

Similarly, the powers of 3 are 3, 9, 27, 81, 243, 729, etc... (which we get by continually multiplying by 3).

Since 243 is in the 5th position, .

Can you do it for powers of 11?