Question 3 requires the polynomial model, say P(x) where x is the month, 1 for January, 2 for February, and so
P(7) is the value for July.
So if you have already found the polynomial for question 3, it is a question of substituting the proper month (July) to find P(July) as the number of birds in July.
I can find the finite differences, but how do I find the number of birds in July?
owl.bcpnet. net/Algebra%202/ch6/section09/problem_solving.pdf
2 answers
In case you have difficulties also with Q3, there is a good article that show you how to solve a similar problem step-by-step:
http://www.trans4mind.com/personal_development/mathematics/series/polynomialEquationDifferences.htm
http://www.trans4mind.com/personal_development/mathematics/series/polynomialEquationDifferences.htm