Answer:
As per the statement:
A ball is dropped from a certain height.
The function is given as:

where,
f(n) represents the height in feet
n represents the number of times the ball bounces.
for n = 0
f(0) = 9
Initial height = 9
for n = 1

For n = 2
and so on...
Since;

⇒

In general:

or

therefore, 0.7 represents the ball bounces to 70% of its previous height with each bounce.