The revenue $\displaystyle R$ (in dollars) from renting $\displaystyle x$ apartments can be modeled by:

$\displaystyle R=2x(900+32x-x^2)$

Find the additional revenue when the number of rentals is increased from 14 to 15, and find the marginal revenue when x=14.

How can I differentiate this problem and solve it down?

Thanks for reading. :-]