Please help! I will mark as brainliest. <3

Answer:
6
Step-by-step explanation:
The length of the rectangle is nine feet less than five times the width. This means that L = 5w - 9. The perimeter, or 2w + 2L, is 54. We can substitute L with 5w - 9 to solve the equation for w.
2w + 2(5w - 9) = 54
2w + 10w - 18 = 54
12w = 72
w = 6