linear cost function

Assume that the following has a linear cost function. Find the cost​ function, C(x), revenue​ function, R(x), and profit​ function, P(x), where x is the number of items produced​ (or sold).

Fixed Cost | Marginal Cost | Item Sells

$200 | $19 | $31

What is the cost​ function?

​C(x)= ______. (Simplify your answer)

What is the revenue​ function?

​R(x)= ______. (Simplify your answer)

What is the profit​ function?

​P(x)= ______. (Simplify your answer)