I FOUND YOUR COMPLETE QUESTION IN OTHER SOURCES.
PLEASE SEE ATTACHED IMAGE.
Part 1:
we must see in the graph the axis of symmetry of the given parabola.
The axis of symmetry is the following vertical line:
Answer:
The height of the javelin above the ground is symmetric about the line t = 2 seconds:
Part 2:
we must see the time t for which the javelin reaches a height of 20 feet for the first time.
We have that when evaluating t = 1, the function is:

To do this, just look at the graph.
Then, we must observe the moment when it returns to be 20 feet above the ground.
For this, we have from the graph that:

Therefore, a height of 20 feet is again reached in 3 seconds.
Answer:
The javelin is 20 feet above the ground for the first time at t = 1 second and again at t = 3 seconds
Answer:
<h3>

</h3>
Step-by-step explanation:
3, 9, 15, 21, ...
9-3 = 6; 15-9 = 6; 21-15 = 6 ⇒ d = 6
first term: a = 3
difference: d = 6
so the formula:
and:

Answer:
You can find its average speed.
Step-by-step explanation:
To find average speed you can divide distance by time which has been given.
Answer:
25 kilometers per hour
Step-by-step explanation:
I just simply made it into a proportion of 50/2=x/1 and 50 divided by 2 is 25. hopefully that help you.