standard logarithm rules log rules log rules http://www.purplemath.com/modules/logrules.htm log rule Log Rules log rules standard logarithm rules PurpleMath: Basic Log Rules Basic Logarithmic Properties purplemath.com Basic Logarithmic Properties log rules standard logarithm rules Basic Log Rules Log Rules log rules Basic Log Rules/Expanding Logs log rule log rule log rule Basic Log Rules log rules http://www.purplemath.com/modules/logrules.htm log rules Notes log rules