Answer:
Part 1) Descending Rate = -2,000 ft/min
Part 2) Starting altitude value is 33,000 ft
Part 3) The linear equation for the plane's altitude (y) as a function of time (x) is: 
Part 4) The information not used for the equation is that the plane was travelling for 4 hours to cover 1800 miles before starting the descent
Step-by-step explanation:
Part 1)
The rate at which the airplane descends is given by the difference between final and initial altitude (17,000 ft-33,000 ft) divided the elapsed time (8 minutes):
Part 2)
When graphing the descent (that is the plane's altitude as a function of time), the starting value for the altitude should be 33,000 ft
Part 3)
We can build the equation of the plane's altitude as a function of time in slope y-intercept form y = m x + b
by noticing that the slope "m" stands for the rate of descent that we found in part 1), and then using the information that at time zero (when the plane starts its descent), its altitude is 33000 ft:
with this information about the intercept "b", we can write the final expression for the plane's altitude as a function of time during its descent as:
Part 4)
The information that was not used to write the descent equation was the initial details about how long the plane traveled (4 hours) and for 1800 miles.
