Find the dimensions of the rectangular box given the volume and relationships between its dimensions.
Write the equation representing the relationship.
The height of the box is \( 8 \, \text{ft} \), and the length \( L \) is \( 2 \, \text{ft} \) longer than thrice the width \( x \). The volume \( V \) is given by the equation:
\[
V = L \cdot W \cdot H = (3x + 2) \cdot x \cdot 8 = 680
\]
This simplifies to:
\[
24x^2 + 16x - 680 = 0
\]
Factor the polynomial.
The polynomial \( 24x^2 + 16x - 680 \) can be factored as:
\[
8 \left(x - 5\right) \left(3x + 17\right) = 0
\]
Solve for \( x \).
Setting each factor to zero gives:
\[
x - 5 = 0 \quad \Rightarrow \quad x = 5
\]
\[
3x + 17 = 0 \quad \Rightarrow \quad x = -\frac{17}{3} \quad (\text{not valid since width cannot be negative})
\]
Thus, the width is:
\[
\boxed{x = 5} \, \text{ft}
\]
Calculate the length.
Using the width to find the length:
\[
L = 3x + 2 = 3(5) + 2 = 15 + 2 = 17 \, \text{ft}
\]
Thus, the length is:
\[
\boxed{L = 17} \, \text{ft}
\]
The width of the box is \( \boxed{5} \, \text{ft} \) and the length is \( \boxed{17} \, \text{ft} \).
The width of the box is \( \boxed{5} \, \text{ft} \).
The length of the box is \( \boxed{17} \, \text{ft} \).