a.  b. 

First of all what you thought was "In" was really "ln" which
means "natural logarithm" or loge where e = 2.718...

Secondly, you don't plug anything into a calculator.  The 
calculator is a nice tool for saving time, but it doesn't save 
you from having to learn the rules of logarithms, and they
are all that are required here:

For (a) and (b) you need to learn the rule of logarithms:



For (b) you need to learn the rule of logarithms:



--------------------
(a)


Using the first rule above on the left side, we have



which you can easily solve and get



(b)


Using the second rule above on the left side, we have



Now we raise e to the both sides power:



Using the first rule on the left side, and
erasing the 1 exponent on the right, we have:



or



Edwin