
Arturo O. answered 03/01/20
Experienced Physics Teacher for Physics Tutoring
Since 2015 is 5 years after 2010, plug in x=5 and evaluate to get P(5). That gives the total at 2015. To get the initial population at 2010, plug in x=0 and evaluate P(0). The increase is just the difference between P(5) and P(0):
ΔP = P(5) - P(0)
You have the formula for P(x), so just plug in the numbers.