To find the area of the rectangular garden, we can multiply the functions that represent the length and width of the garden.
Given:
- Length: \( f(x) = x + 4 \)
- Width: \( g(x) = 2x - 1 \)
The area \( A(x) \) of the rectangle can be expressed as: \[ A(x) = f(x) \cdot g(x) = (x + 4)(2x - 1) \]
Now, let's compute this product: \[ A(x) = (x + 4)(2x - 1) = x(2x - 1) + 4(2x - 1) \] \[ = 2x^2 - x + 8x - 4 \] \[ = 2x^2 + 7x - 4 \]
So, the function that represents the area of the rectangular garden is: \[ A(x) = 2x^2 + 7x - 4 \]
Next, let's determine the domain of this function. Since the length and width represent physical dimensions of the garden, we need both functions to be positive:
-
For the length \( f(x) = x + 4 \):
- Set \( x + 4 > 0 \)
- \( x > -4 \)
-
For the width \( g(x) = 2x - 1 \):
- Set \( 2x - 1 > 0 \)
- \( 2x > 1 \)
- \( x > \frac{1}{2} \)
The more restrictive condition is \( x > \frac{1}{2} \). Therefore, the domain of the area function \( A(x) = 2x^2 + 7x - 4 \) is: \[ \text{Domain: } x > \frac{1}{2} \]
Finally, combining both parts, we can conclude:
- The function representing the area of the rectangular garden is \( A(x) = 2x^2 + 7x - 4 \).
- The domain is \( x > \frac{1}{2} \).