Write the Word or Phrase That Best Completes Each Statement $\mathrm { p }$

Write the word or phrase that best completes each statement or answers the question.
-The price $\mathrm { p }$ and $\mathrm { x }$ , the quantity of a certain product sold, obey the demand equation
$$p = - \frac { 1 } { 10 } x + 100 , \{ x \mid 0 \leq x \leq 1000 \}$$
a) Express the revenue $R$ as a function of $x$ .
b) What is the revenue if 450 units are sold?
c) Graph the revenue function using a graphing utility.
d) What quantity $x$ maximizes revenue? What is the maximum revenue?
e) What price should the company charge to maximize revenue?