Discuss the concavity of the graph of the function by determining the open intervals on which the graph is concave upward or downward.
f(x) = −
1
3
x3 − 9x2 − 7x − 9

Ben and cam are scuba diving. ben is 15.815.8 meters below the surface of the water. cam is 4.24.2 meters above ben. what is cam's position relative to the surface of the water? choose 1 choose 1 (choice a) a 11.611.6 meters above the surface of the water (choice b) b 11.611.6 meters below the surface of the water (choice c) c 2020 meters above the surface of the water (choice d) d 20 meters below the surface of the water