Need help with part A and B

A certain firm's profit function is T (x) = 30x - - -x2 - 200 where x represents the (positive) quantity of output produced by the firm and n(x) represents the firm's profit. a. Find the first and second derivatives of the profit function. b. Using the appropriate calculus techniques, find the value of x at which profit reaches its maximum value. (Be sure to use both of the derivatives from part (a).)