A deli sells 500 sandwiches per day at a price $10 each. If the deli rises the price to $12, the sales drop to 300 sandwiches per day.

(a) Find the demand function q(x), where x is the price, assuming that q(x) is a linear function. Make sure to determine the domain of q(x). (Hint: both x and q(x) must be non-negative).

(b) Now suppose that instead of the linear model you decide to use an exponential model q(x) = Cax . Find C and a