The following table shows the length and width of a rectangle:
\begin{tabular}{|l|l|l|}
\hline
& Length & Width \\
\hline
Rectangle A & [tex]$4x + 5$[/tex] & [tex]$3x - 2$[/tex] \\
\hline
\end{tabular}

Which expression is the result of the perimeter of rectangle [tex]$A$[/tex] and demonstrates the closure property?

A. [tex]$2x + 6$[/tex]; the answer is a polynomial

B. [tex]$2x + 6$[/tex]; the answer may or may not be a polynomial

C. [tex]$14x + 6$[/tex]; the answer may or may not be a polynomial

D. [tex]$14x + 6$[/tex]; the answer is a polynomial



Answer :

To determine the perimeter of rectangle [tex]\( A \)[/tex], we need to apply the formula for the perimeter of a rectangle, which is [tex]\( P = 2 \times (\text{Length} + \text{Width}) \)[/tex].

Given:
- Length [tex]\( = 4x + 5 \)[/tex]
- Width [tex]\( = 3x - 2 \)[/tex]

Let's calculate the perimeter step-by-step.

1. Find the sum of the length and the width:

[tex]\[ \text{Length} + \text{Width} = (4x + 5) + (3x - 2) \][/tex]

2. Combine the like terms:

[tex]\[ (4x + 3x) + (5 - 2) = 7x + 3 \][/tex]

3. Multiply the sum by 2 to find the perimeter:

[tex]\[ P = 2 \times (7x + 3) \][/tex]

4. Distribute the 2 to each term inside the parentheses:

[tex]\[ P = 2 \times 7x + 2 \times 3 = 14x + 6 \][/tex]

So, the expression for the perimeter of rectangle [tex]\( A \)[/tex] is [tex]\( 14x + 6 \)[/tex].

Now, regarding whether this expression demonstrates the closure property:
- The closure property in the context of polynomials states that the sum, difference, and product of polynomials is also a polynomial.
- Since [tex]\( 14x + 6 \)[/tex] is an expression that is linear in form (a polynomial of degree 1), it demonstrates the closure property when considering addition and multiplication of polynomials.

Thus, the expression [tex]\( 14x + 6 \)[/tex] is a polynomial, and the correct answer from the given options is:

[tex]$14x + 6$[/tex]; the answer is a polynomial.