Arectangular garden has a length 8 more than the width. there is a 4 foot sidewalk around the outside of the garden. the area of the side walk is 320. what is the dimensions of the rectangular garden?

  The length of a rectangular garden is 8 feet longer than the width.

L = W + 4

Area of garden: W(W + 8)

Area of sidewalk Plus garden: (W + 8)(W + 16)

Subtract the areas to get the area of the sidewalk

(W + 8)(W + 16) - W (W + 8) = 320

W^2 + 24W + 128 - W^2 - 8W = 320

16W = 192

W = 12

So L = 12 + 8 = 20