Answer:
a) We want to find
and if we replace x=3 into p(x) we got:

b) We want to find
and if we replace x=13 into p(x) we got:

c) ![p(13)-p(3) = [0.03*(13)^2 +0.42*13 +9.63]-[0.03*(3)^2 +0.42*3 +9.63] = 20.16-11.16 = 9](https://tex.z-dn.net/?f=%20p%2813%29-p%283%29%20%3D%20%5B0.03%2A%2813%29%5E2%20%2B0.42%2A13%20%2B9.63%5D-%5B0.03%2A%283%29%5E2%20%2B0.42%2A3%20%2B9.63%5D%20%3D%2020.16-11.16%20%3D%209)
d) 
If we use the result from part c we have:

And the interpretation for this case would be:
It represents the average rate of change in price from 1996 to 2006.
Step-by-step explanation:
For this case we have the following function given:

Part a
We want to find
and if we replace x=3 into p(x) we got:

Part b
We want to find
and if we replace x=13 into p(x) we got:

Part c
For this case we want to find
and we have from the results of part a and b this:
![p(13)-p(3) = [0.03*(13)^2 +0.42*13 +9.63]-[0.03*(3)^2 +0.42*3 +9.63] = 20.16-11.16 = 9](https://tex.z-dn.net/?f=%20p%2813%29-p%283%29%20%3D%20%5B0.03%2A%2813%29%5E2%20%2B0.42%2A13%20%2B9.63%5D-%5B0.03%2A%283%29%5E2%20%2B0.42%2A3%20%2B9.63%5D%20%3D%2020.16-11.16%20%3D%209)
Part d
For this case we want to find:

If we use the result from part c we have:

And the interpretation for this case would be:
It represents the average rate of change in price from 1996 to 2006.