Answer:
"decreasing at a constant rate" suggests linear relationship.
Your description for year 2013 said, "dropped 5400". That means, the population in year 2013 was 5700-5400=300. Description did not say "dropped TO 5400".
According to the description as posted,
points (x,y) for x being year past 2010 and y being population
(0, 5700) and (13, 300).
Equation for the line:
y=%28%28300-5700%29%2F%2813%29%29x%2B5700
highlight%28y=-%285400%2F13%29x%2B5700%29
which is probably not the actual equation you want, but the method should be clear and you can fix the possible mistake in your description, and find the actual equation for your corrected description.
Step-by-step explanation:
Where,
