Melanie and Denzel are buying strawberries to make a cobbler. The friends have $12 to spend, and strawberries cost $3.99 per pound. Which function represents the amount of money Melanie and Denzel have left, f(x) , after buying x pounds of strawberries?

In order to solve for the volume, we have to form a couple equations from the given:

w = 4h - "The width of the sandbox is 4 times its height."
l = 2h + 8 - "The length of the sandbox os 8 ft more than 2 times its height."
w * l * h = 40 - "You have ft^3 of sand available to fill this sandbox"

Alter the values of 'w' and 'l' in 'w * l * h = 40':
(4h) * (2h + 8) * h = 40
Multiply:
(8h^2 + 32h) * h = 40
8h^3 + 32h^2 = 40

Divide all the numbers by eight:
h^3 + 4h^2 = 5
Factor the h^2 out:
h^2(h + 4) = 5
h = 1 (This looks like the only possible number)

We now know that h = 1.
Recall the equations we formed at the start.
w = 4(1) = 4
l = 2(1) + 8 = 10

The height is 1 foot, the width is 4 feet, and the length is 10 feet.