It's fairly simple if you remember the basic rules of logarithms.
1) Log a - log b = log (a/b) --> assume it is all to the same base e.g. ln.
2) log a + log b = log (a * b)
3) log (a^b) = b * log a
Now look at the problem.
=--> from rule 1 above
Call this eqn (A)
Now look at what you have inside the brackets.
=
=-----> remember that (a^m)/(a^n) = a^(m - n)
=
Now going back to eqn A
=
=------> from rule 3 above
Hope you got it now. Let me know if it is not clear :)