Logarithm help

Well, i have an exam in a few weeks and lets say i am not as sharp as i should be with logs.
i understand the basics, log[base a] b = c gets converted to a^c=b. that is simple enough but, regardless of hours net searching i have come up with little. also i dont have any supplied text books which give more than the simple rules either.

well the questions that need to be answered are:





they need to be simplified and solved respectively.


im not asking for you to do my homework but rather to give me at least a technique or a rule in which to apply on the appropriate question.
as i said the text book only gives the simple, basic rules but not ones that could be applied to the above questions or similar.

any help at all in this would be invaluable and appreciated the highest level