glenn101,
Solution to the first problem is correct, Good!
Here I have solved two problems for you:-

Thanks for the answers ganesh!
I havn't been taught those sorts of logs before, with surds and same bases.
Looks interesting.
Thanks again

and no I havn't careless, I've only been taught how to deal with same bases, nothing advanced. Next year we deal with e and I'm guessing we will also be taught the change of base formula.

Ganesh i havent been taught that far yet... but for me the base change formula is using base 10 so we can use calculators...

so i always do this:

log 25 (100) = log 10 (100) * log 10 (25)

so always base 10.
but i can see what you mean by that formula and example.

Its a pleasure helping you with logarithms,
logs are such an important tool in calculations!
For my Practical Final-I at University, I had to find the Young's Modulus and this would have been extremely difficult without logarithms or a scientific calculator! We were not allowed to use calculators!

Yeah, logs have always been my favorite topic, its easy for me to understand.
Then comes calculus and trig.