Answer:
Width is 5 ft, length is 10ft.
Plug in the information given from the problem, in which the width is x, and the length is x + 5.
x(x+5) = x^2 + 5x
(x+4)(x+9) = x^2 + 13x +36
x^2 + 13x +36 - (x^2 + 5x) = 76
Simplify and result in 8x = 40
x = 5, which makes the length 10.