The total revenue R earned per day (in dollars) from a pet-sitting service is given by the following equation, where p is the price charged per pet (in dollars).
R(p) = −12p2 + 180p
(a) Find the revenue earned for each price per pet given below.
R($4) $
R($5) $
R($6) $

(b) Find the unit price that will yield a maximum revenue.
$
per pet

What is the maximum revenue?
$

Explain your results.