AP Calculus AB, concavity and the second derivative test

1. Solve. 3 = =8, 76 C. 1. O 3.) A certain commodity is marketed by a business at a price of $400 per unit. The total cost of marketing x units of the commodity is C = 0.02x + 160x + 400,000. How many units of the commodity must be sold for maximum profit? (Recall profit = revenue - cost.)