The weekly demand for the Pulsar 40-in. high-definition television is given by the demand equation p = -0.04x + 561 (0 <= x <= 12,000), where p denotes the wholesale unit price in dollars and x denotes the quantity demanded. The weekly total cost function associated with manufacturing these sets is given by C(x) = 0.000001x^3 - 0.01x^2 + 400x + 80,000, where C(x) denotes the total cost incurred in producing x sets. Find the level of production that will yield a maximum profit for the manufacturer. Hint: Use the quadratic formula. (Round your answer to the nearest whole number.)