Answer:
,,follows:
(w + 9)(w - 2) = 0.
That is:
(w + 9) = 0, or (w - 2) = 0.
Now (w + 9) = 0 would mean w = -9 feet. But that's impossible because dimensions are always positive numbers. So discard that “extraneous” solution,
The other solution is (w - 2) = 0, so w, the width is 2 feet, and since the length is 7 feet longer than the width, the length is 9 feet, and the area is (2 feet) x (9 feet), which is 18 square feet, as stated in the problem.