Answer:
980 feet
Step-by-step explanation:
Because the length is 5 times the width, you can write it as 5x with x as the width. Then you can set it up as 5x + x = 84 for l + w = p, and solve for x. You'll find that x is 14, and 14 times 5 is 70, so you would multiply 70 by 14 to get 980.