Answer:
a) The demand function is

b) The nightly revenue is

c) The profit function is

d) The entrance fees that allow Swing Haven to break even are between 10.03 and 23.41 dollars per guest.
Step-by-step explanation:
a) Lets find the slope s of the demand:

Since the demand takes the value 79 in 7, then

b) The nightly revenue can be found by multiplying q by p

c) The profit function is obtained from substracting the const function C(p) from the revenue function R(p)

d) Lets find out the zeros and positive interval of P. Since P is a quadratic function with negative main coefficient, then it should have a maximum at the vertex, and between the roots (if any), the function should be positive. Therefore, we just need to find the zeros of P

Therefore, the entrance fees that allow Swing Haven to break even are between 10.03 and 23.41 dollars per guest.
The Answer: (-b + 15) (15 - b)
We are given an equation:

This is an equation of a circle. General form of a circle equation is:

Where:
a = x coordinate of a center
b = y coordinate of a center
r = radius of a circle
Motion detector can detect person anywhere within a boundary. The greatest distance at which detector can detect is at the edge of a circle. That distance, between detector and edge of circle, is equal to radius.
From the equation we have:

The greatest distance at which person can be detected is 4ft.