The design for a rectangular solid shipping container has a volume of 24x3+6x2−9x

where x represents inches. The box has a height of 3x
. Find the container’s cross-sectional area using polynomial division.

1 answer

To find the cross-sectional area of the rectangular solid shipping container, we need to divide the volume polynomial by the height polynomial. The volume \( V \) of the container is given by:

\[ V = 24x^3 + 6x^2 - 9x \]

The height \( h \) of the container is:

\[ h = 3x \]

To find the cross-sectional area \( A \), we divide the volume \( V \) by the height \( h \):

\[ A = \frac{V}{h} = \frac{24x^3 + 6x^2 - 9x}{3x} \]

We can perform polynomial long division to simplify this expression.

  1. Divide the leading term of the numerator by the leading term of the denominator:

    \[ \frac{24x^3}{3x} = 8x^2 \]

  2. Multiply the entire denominator by this result and subtract it from the numerator:

    \[ (24x^3 + 6x^2 - 9x) - (8x^2 \cdot 3x) = 24x^3 + 6x^2 - 9x - (24x^3) = 6x^2 - 9x \]

  3. Now divide the leading term of the remaining polynomial by the leading term of the denominator again:

    \[ \frac{6x^2}{3x} = 2x \]

  4. Multiply the entire denominator by this result and subtract again:

    \[ (6x^2 - 9x) - (2x \cdot 3x) = 6x^2 - 9x - (6x^2) = -9x \]

  5. Now divide the leading term of the remaining polynomial by the leading term of the denominator again:

    \[ \frac{-9x}{3x} = -3 \]

  6. Multiply the entire denominator by this result and subtract again:

    \[ (-9x) - (-3 \cdot 3x) = -9x + 9x = 0 \]

Now we combine all the terms we've obtained:

\[ A = 8x^2 + 2x - 3 \]

Therefore, the cross-sectional area of the container is:

\[ \boxed{8x^2 + 2x - 3} \]