A plane is on its approach to land on the runway. The jet's height above the ground is given in feet as a function of the time in seconds. The following table tracks the plane as it lands:

Calculate the slope. Use the formula -
What is the significance of the sign of the slope?
a. The plane is losing altitude.
b. The plane is gaining altitude.
C The plane is remaining at a constant height.
d. The plane is losing altitude at a rate of 500 feet/second.