The following table shows the length and width of a rectangle:

\begin{tabular}{|l|l|l|}
\hline
& Length & Width \\
\hline
Rectangle [tex]$A$[/tex] & [tex]$3x + 5$[/tex] & [tex]$2x - 3$[/tex] \\
\hline
\end{tabular}

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

A. [tex]$10x + 4$[/tex]; the answer is a polynomial
B. [tex]$2x + 4$[/tex]; the answer is a polynomial
C. [tex]$10x + 4$[/tex]; the answer may or may not be a polynomial
D. [tex]$2x + 4$[/tex]; the answer may or may not be a polynomial



Answer :

To determine the correct expression for the perimeter of rectangle [tex]\( A \)[/tex] and to verify the closure property, follow these steps:

1. Identify the Expressions for Length and Width:
- The length of rectangle [tex]\( A \)[/tex] is given as [tex]\( 3x + 5 \)[/tex].
- The width of rectangle [tex]\( A \)[/tex] is given as [tex]\( 2x - 3 \)[/tex].

2. Formula for Perimeter of a Rectangle:
The formula to calculate the perimeter [tex]\( P \)[/tex] of a rectangle is:
[tex]\[ P = 2 \times (\text{Length} + \text{Width}) \][/tex]

3. Substitute the Given Length and Width:
Substitute the given expressions for length and width into the perimeter formula:
[tex]\[ P = 2 \times ( (3x + 5) + (2x - 3) ) \][/tex]

4. Simplify the Expression Inside the Parentheses:
Combine like terms inside the parentheses:
[tex]\[ (3x + 5) + (2x - 3) = 3x + 2x + 5 - 3 = 5x + 2 \][/tex]

5. Calculate the Perimeter:
Multiply by 2 to get the expression for the perimeter:
[tex]\[ P = 2 \times (5x + 2) = 2 \times 5x + 2 \times 2 = 10x + 4 \][/tex]

6. Analyze the Resulting Expression:
The resulting expression for the perimeter of rectangle [tex]\( A \)[/tex] is [tex]\( 10x + 4 \)[/tex].

7. Check the Closure Property:
The closure property states that performing arithmetic operations (addition, subtraction, multiplication, or division by a non-zero number) on polynomials will result in another polynomial. Here, [tex]\( 10x + 4 \)[/tex] is a polynomial because it is a linear expression involving terms with non-negative integer exponents and does not involve any division operations.

Therefore, the correct expression for the perimeter of rectangle [tex]\( A \)[/tex] is [tex]\( 10x + 4 \)[/tex], and it is a polynomial.

[tex]\[ \boxed{10x + 4; \text{ the answer is a polynomial}} \][/tex]