In a free market economy the supply curve for a commodity is the number of items of a product that can be made available at different prices, and the demand curve is the number of items the consumer w...In a free market economy the supply curve for a commodity is the number of items of a product that can be made available at different prices, and the demand curve is the number of items the consumer will buy at different prices. The supply curve for a product is y=3.5x−14 and the demand curve for the same product is y=−2.5x+34, where x is the price and y the number of items produced.