The graph below shows the height of Cindy's model rocket during the course of its flight. Flight of Cindy's Rocket
у
Height (in feet)
22
20
18
16
14
.5 12
10
6
4.
2.
0 1 2 3 4 5 6 7 8 9
Time (in seconds)
Which of these equations can be used to find the height of the rocket at any time during its flight?
A y = 9x
B. y = x2 - 81
C y = -x2 + 9x
D y = 9 - 9x2