The altitude of an airplane coming in for a landing is represented by the equation shown below, where y represents the altitude, in feet, of the airplane and x represents the number of minutes the plane has been descending (going down):

y = -578x + 18,995



Part A:

What would the y-values in the table be when x = 0, 5, 8, 10, 30?

x

(number of minutes the plane has been descending)

y

(altitude)

0
5
8
10
30


Part B:

What is the altitude of the airplane after 5 minutes? After 30 minutes? Write your answers as two ordered pairs (x,y).



Part C:

Which ordered pair (from the table in part B) represents the initial value? What does the initial value represent in this problem? (1-2 sentences)



Part D:

What is the rate of change in this equation? What does the rate of change represent in this problem? (1-2 sentences)