To find the area of the path, we'll need to find the area of the space with the path and subtract the area of the inner space.
Total area: (80 + w)(50 + w)
Inner area: 80 x 50
Area of the path: (80 + w)(50 + w) - (80 x 50)
(4000 + 80w + 50w + w^2) - (4000)
4000 + 130w + w^2 - 4000
w^2 + 130w
w(w + 130)
Expression for the total area: (80 + w)(50 + w)
Expression for the area of the path: w(w + 130)
Hope this helps!! :)