answer and how to get the answer

The marginal revenue (in thousands of dollars) from the sale of x handheld gaming devices is given by the following function. 2 R'(x) = 4x (x2 + 27,000) (a) Find the total revenue function if the revenue from 120 devices is $7,564. (b) How many devices must be sold for a revenue of at least $41,000? E) (a) The total revenue function is R(x) = D, given that the revenue from 120devices is $7,564. (Round to the nearest integer as needed.) (b) devices must be sold to generate a revenue of at least $41 ,000. (Type a whole number.)