1,600 principal earning 7%, compounded semi-annually, after 33 years

Which of the following statement about pascal's triangle are true?

Asocial networking site currently has 400,000 active members, and that figure is predicted to increase by 32% each year. the following expression represents the number of active members on the site after t years.

If f(x) = 4x - 3 and g(x) = x + 4, find (f - g) (x)