The length of the rectangular delivery box must be equal to 4 inches.
Let the length of the box be L.
Let the width of the box be W.
Let the height of the box be H.
<u>Given the following data:</u>
- Volume of box = 224 cubic inches.
Translating the word problem into an algebraic expression;
......equation 1
......equation 2.
Mathematically, the volume of a rectangular solid is given by the formula;
.....equation 3.
Substituting the values into equation, we have;
![224 = L * (3 + L) * (4 + L)\\\\224 = (3L + L^{2})* (4 + L)\\\\224 = 12L + 3L^{2} + 4L^{2} + L^{3} \\\\224 = 12L + 7L^{2} + L^{3}](https://tex.z-dn.net/?f=224%20%3D%20L%20%2A%20%283%20%2B%20L%29%20%2A%20%284%20%2B%20L%29%5C%5C%5C%5C224%20%3D%20%283L%20%2B%20L%5E%7B2%7D%29%2A%20%284%20%2B%20L%29%5C%5C%5C%5C224%20%3D%2012L%20%2B%203L%5E%7B2%7D%20%2B%204L%5E%7B2%7D%20%2B%20L%5E%7B3%7D%20%5C%5C%5C%5C224%20%3D%2012L%20%2B%207L%5E%7B2%7D%20%2B%20L%5E%7B3%7D)
Rearranging the polynomial, we have;
![L^{3} + 7L^{2} + 12L - 224 = 0](https://tex.z-dn.net/?f=L%5E%7B3%7D%20%2B%207L%5E%7B2%7D%20%2B%20%2012L%20-%20224%20%3D%200)
We would apply the remainder theorem to solve the polynomial.
According to the remainder theorem, if a polynomial P(x) is divided by (x - r) and there is a remainder R; then P(r) = R.
When x = 3
![(x - 3) = 0\\x = 3](https://tex.z-dn.net/?f=%28x%20-%203%29%20%3D%200%5C%5Cx%20%3D%203)
![P(3) = 3^{3} + 7(3^{2}) + 12(3) - 224\\\\P(3) = 27 + 7(9) + 36 - 224\\\\P(3) = 27 + 63 + 36 - 224 = -98 \neq 0](https://tex.z-dn.net/?f=P%283%29%20%3D%203%5E%7B3%7D%20%2B%207%283%5E%7B2%7D%29%20%2B%2012%283%29%20-%20224%5C%5C%5C%5CP%283%29%20%3D%2027%20%2B%207%289%29%20%20%2B%2036%20-%20224%5C%5C%5C%5CP%283%29%20%3D%2027%20%2B%2063%20%2B%2036%20-%20224%20%3D%20-98%20%5Cneq%200)
We would try with 4;
![P(4) = 4^{3} + 7(4^{2}) + 12(4) - 224\\\\P(4) = 64 + 7(16) + 48 - 224\\\\P(4) = 64 + 112 + 48 - 224\\\\P(4) = 224 - 224 = 0](https://tex.z-dn.net/?f=P%284%29%20%3D%204%5E%7B3%7D%20%2B%207%284%5E%7B2%7D%29%20%2B%2012%284%29%20-%20224%5C%5C%5C%5CP%284%29%20%3D%2064%20%2B%207%2816%29%20%20%2B%2048%20-%20224%5C%5C%5C%5CP%284%29%20%3D%2064%20%2B%20112%20%2B%2048%20-%20224%5C%5C%5C%5CP%284%29%20%3D%20224%20%20-%20224%20%3D%200)
Therefore, 4 is one of its roots.
Hence, the length of the rectangular delivery box must be equal to 4 inches.
Find more information on polynomial here: brainly.com/question/10689855