8.9% is equal to 0.089 because a percent is over a 100. So, you can just multiply the ROI by the investment to get:

Your answer is:
$712.
Answer:
d. does not exist
Step-by-step explanation:
The given limits are;
,
and 
We want to find

By the properties of limits, we have;

This gives us;

Division by zero is not possible. Therefore the limit does not exist.