Question 1039802
Use the log rules to say


{{{log(4,(21))=log(4,(3*7))}}}
{{{log(4,(21))=log(4,(3))+log(4,(7))}}}
{{{log(4,(21))=0.7925+1.4037}}}
{{{log(4,(21))=2.1962}}} (this is approximate)


and


{{{log(4,(7/12))=log(4,(7/(3*4)))}}}
{{{log(4,(7/12))=log(4,(7))-log(4,(3*4))}}}
{{{log(4,(7/12))=1.4037-(log(4,(3))+log(4,(4)))}}}
{{{log(4,(7/12))=1.4037-(0.7925+1)}}}
{{{log(4,(7/12))=1.4037-1.7925}}}
{{{log(4,(7/12))=-0.3888}}} (this is also approximate)