Questions 7-9: Until recently. hamburgers at the city sports arena cost $2.80 each. The food concessionaire sold an average of 22,000 hamburgers on game night. When the price was raised to $3.10. hamburger sales dropped off to an average of 19,000 per night. 7. Let a: be the number of hamburgers sold and p(x} be the price at which those hamburgers were sold. Assuming a linear demand curve. write the function p(:c} in the form p(:c} = ms: + b. 8. Find the price of a hamburger that will maximize the nightly hamburger revenue. 9. If the concessionaire has fixed costs of $2500 per night and the variable cost is $0.70 per hamburger. find the price of a hamburger that will maximize the nightly hamburger profit