X intercepts are = 0 and 20
Maximum value = (10,15)
These can simply be read off of the graph.
The intervals of increasing from x = 0-10 and that shows the ball going up. Decreasing from 10-20 and that is the exact opposite.
The rate of change is often referred to as slope. The slope for the section described in part B is -1. It can be used by following the slope formula below:
y2 - y1/x2 - x1