To calculate \((f \cdot g)(x)\), we need to multiply the two functions \(f(x)\) and \(g(x)\):
Given:
- \(f(x) = x\) (length of the rectangle)
- \(g(x) = x + 3\) (width of the rectangle)
Now we compute \((f \cdot g)(x)\):
\[ (f \cdot g)(x) = f(x) \cdot g(x) = x \cdot (x + 3) = x^2 + 3x \]
Now, this product represents the area of the rectangle because the area \(A\) is calculated as \(A = \text{length} \times \text{width}\).
Therefore, the correct response is:
\((f \cdot g)(x) = x^2 + 3x\); It represents the area of the rectangle in square feet.