Answer:
Explanation:
Find the vertex(highest point). This would be at 2.0 seconds so the height of the javelin is symmetric at 2.0 seconds.
To find the next answers, find where the graph is at 20ft-(1.0,20)and (3.0,20). So the javelin is 20 feet above the ground for the first time at 1.0 seconds and then declines to 20 feet again at 3.0 seconds