18. An amusement park ride takes riders to the top of a tower and then drops them. An equation that approximates this ride is h = − 16 t 2 + 64 t + 80, where h is the height of a rider (in feet) after time t (in seconds).
(a) Factor the equation.
(b) How long does it take to reach the highest point of the ride?
(c) How long does the entire ride last?
(d) What is the highest point of the ride?