CCGPS AA 6.1.3 Example 1

The demand for a particular flat-panel television at a store is given by the exponential function , where represents the number of TVs sold that week, and represents the price in dollars. What is the demand level when the TV is priced at $450 versus when it is priced at $400? Which price level will result in higher demand for this TV? Which of the two price levels will yield the most revenue?