Question 147882
Hopefully you mean this,
{{{12+log(10,45)}}}
Remember your log addition rules.
{{{log(10,A*B)=log(10,A)+log(10,B)}}}
Let's make some substitutions.
{{{log(10,A*45)=log(10,A)+log(10,45)=12+log(10,45)}}}
If we equate terms then,
{{{log(10,A)=12}}}
{{{A=10^12}}}
{{{log(10,4.5*10^(13))=12+log(10,45)}}}