There are some rules in logarithm listed below:

1.  log_a (x * y) = log_a x + log_a y

2.  log_x x = 1

3.  log_a (x/y) = log_a x - log_a y

4.  log_a 1 = 0

5.  log_a (x^p ) = p * log_a x

6.  log_a x = 1/log_x a

7.  log_a x = log_b x/log_b a = log x/log a

It is assumed that when base is not given, it is taken as 10