Medical research has shown that between heartbeats, the pressure in the aorta of a normal adult is

Question:

Medical research has shown that between heartbeats, the pressure in the aorta of a normal adult is a function of time in seconds and can be modeled by the equation
P = 95e-0.491t
(a) Use the derivative to find the rate at which the pressure is changing at any time t.
(b) Use the derivative to find the rate at which the pressure is changing after 0.1 second.
(c) Is the pressure increasing or decreasing?