Atriangle has sides of 2,3 and 4 using the law of cosines , a^2+b^2-2abcosc=c^2 what is the value of 2abcosc

Based on what i know about mean, this doesn't add up.

Anew shopping mall is gaining in popularity. every day since it opened, the number of shoppers is 5% more than the number of shoppers the day before. the total number of shoppers over the first 10 days is 1258 how many shoppers were on the first day?

What expression is equivalent to log3(x+4)