X = number of months the ads have been posted f(x) = number of books sold w/in the months the ads have been posted

f(x) = 1000(∛x) + 1000

Books sold after 8 months

f(8) = 1000(∛8) + 1000
f(8) = 1000(2) + 1000
f(8) = 2000 + 1000
f(8) = 3000

3000 books were sold after 8 months
put in a graph