Answer:
We conclude that:

Please also check the attached graph.
Step-by-step explanation:
Given
Given the function

To determine
What is the domain of the function y=-720t + 3600
We know that the domain of the function is the set of input argument values for which the function is real and defined.
Given the function

From the given function, it is clear that the function has no undefined points nor domain constraints.
Therefore, the domain of the function is

Thus, we conclude that:

Please also check the attached graph.
Only i.
If the value is changing by a certain dollar amount every year, this means it is a constant rate of change. If it is changing by a certain percentage every year, this means it is changing at a non uniform, specifically exponential, rate.