Need algebra help with the total product function

if the total product function (output) by using L units of labor input is TP(L) units where

TP(L) = aL+bL^2 −cL^3,a > 0,b > 0,c > 0.

(a)Find the expression for the marginal product of the Lth labor input, which is

TP(L)−TP(L−1).

(b) Take a = 100, b = 1 and c = 1 to answer the remaining parts. Find the marginal product of the second labor input.

(c)Find the marginal product of the fifth labor input. (d)Recall marginal product is defined using the derivatives as

MP(L) =dTP(L)/dL