here is the question in the picture . please make sure the answer to be clear please . and if you can to be on computer not hand write to be more cleare

3. (6 points) The price - demand equation for hamburgers at a fast - food restaurant is x + 400p = 3000. Currently, the price of hamburger is $4. If price will increase by 5%, will revenue increase, or decrease? Currently, the price of hamburger is $2. If price will decrease by 5%, will revenue increase, or decrease? What price will maximize revenue from selling hamburgers