The answer would be B check the picture for work.
Here it is given that the width is x ft and total length of the fence is 2400 ft .
Let the length be y ft
So we have

Let A represents area, and area is the product of length and width .
So we get

Substituting the value of y, we will get

Second part
The area is maximum at the vertex, and vertex is

And

And that's the required dimensions .
4.56 rounded to the nearest whole number is 5
Answer:
(5r-4)(4r^(2)+3)
Step-by-step explanation:
Hope it helps