Desmond, an urban planner, is going to build a new feature in his city's largest park. The feature will include a rectangular garden and surrounding walkway. The garden will be twice as long as it is wide, and the walkway will be 4 feet wide all the way around. To stay within his budget, Desmond decides that the feature will have a total area of approximately 800 square feet. The diagram models the feature Desmond is designing, where x is the width of the garden. Which equation can you use to find the width of the garden?