The length of a rectangular garden is given by the function f(x)=x+4

. The width of a rectangular garden is given by the function g(x)=2x−1
. What function represents the area of the rectangular garden? What is the domain?(1 point)
Responses

(f⋅g)(x)=2x2+7x−4
and the domain of (f⋅g)(x)
is (−∞,∞)
.
open paren f times g close paren of x is equal to 2 x squared plus 7 x minus 4 and the domain of open paren f times g close paren of x is open paren negative infinity comma infinity close paren .

(f⋅g)(x)=3x+3
and the domain of (f⋅g)(x)
is (−∞,∞)
.
open paren f times g close paren of x is equal to 3 x plus 3 and the domain of open paren f times g close paren of x is open paren negative infinity comma infinity close paren .

(f⋅g)(x)=3x+3
and the domain of (f⋅g)(x)
is x≥12
.
open paren f times g close paren of x is equal to 3 x plus 3 and the domain of open paren f times g close paren of x is x is greater than or equal to 1 half .

(f⋅g)(x)=2x2+7x−4
and the domain of

1 answer

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:

  1. For the length \( f(x) = x + 4 \):

    • Set \( x + 4 > 0 \)
    • \( x > -4 \)
  2. 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 \( x > \frac{1}{2} \).