This is just a formula game...  If you take Calculus, these rules can make impossible problems really easy!
 

1 )  log to the base b( xy ) = log to the base b( x ) + log to the base  b( y )

     Here's an example that you can double-check on your calculator
     to see if this really works:

log( 10 ) = log( 2 * 5 ) = log( 2 ) + log( 5 )

 

2 )  log to the base b( x / y ) = log to the base b( x ) - log to the base b( y )

     Check this on your calculator:

Ln( 25 ) = Ln( 50 / 2 ) = Ln( 50 ) -  Ln( 2 )

 

     Finally, there's our old friend:

3 )  log to the base b( x^( p ) ) = p * log to the base b( x )

     Check this on your calculator:

log( 9 ) = log( 3^( 2 ) ) = 2 * log( 3 )