Maximizing profit the quantity demanded each month of the

Question

Question: MAXIMIZING PROFIT The quantity demanded each month of the Walter Serkin recording of Beethoven's Moonlight Sonata, manufactured by Phonola Record Industries, is related to the price/compact disc. The equation

p = -0.00042x + 6             (0 ≤ x ≤ 12,000)

Where p denotes the unit price in dollars and x is the number of discs demanded, relates the demand to the price. The total monthly cost (in dollars) for pressing and packaging x copies of this classical recording is given by

C(x) = 600 + 2x - 0.00002x²              (0 ≤ x ≤ 20,000) 

To maximize its profits, how many copies should Phonola produce each month?