During the summer months Terry makes and sells necklaces on the beach. Terry notices that if he lowers the price,
he can sell more necklaces, and if he raises the price than he sells fewer necklaces. The table below shows how the
number of necklaces sold in one day depends on the price (in dollars).
(a) Find a linear function of the form
that best fits these data, using least squares.

(b) Find the revenue (number of items sold times the price of each item) as a function of price .
.

(c) If the material for each necklace costs Terry dollars, find the profit (revenue minus cost of the
material) as a function of price .
.

(d) Finally, find the price that will maximize the profit.
.