Join IDNLearn.com to access a wealth of knowledge and get your questions answered by experts. Get accurate and detailed answers to your questions from our dedicated community members who are always ready to help.

The width of a rectangle measures [tex]\((k+3)\)[/tex] centimeters, and its length measures [tex]\((k-9)\)[/tex] centimeters. Which expression represents the perimeter, in centimeters, of the rectangle?

A. [tex]\(-8 + 4k\)[/tex]
B. [tex]\(8k - 16\)[/tex]
C. [tex]\(2k - 6\)[/tex]
D. [tex]\(-12 + 4k\)[/tex]


Sagot :

To find the expression that represents the perimeter of a rectangle, we need to follow these steps:

1. Understand the Definitions:
- The width of the rectangle is given as [tex]\( k + 3 \)[/tex] centimeters.
- The length of the rectangle is given as [tex]\( k - 9 \)[/tex] centimeters.

2. Formula for Perimeter:
- The perimeter [tex]\( P \)[/tex] of a rectangle is given by the formula:
[tex]\[ P = 2(\text{length} + \text{width}) \][/tex]

3. Substitute the Given Expressions into the Formula:
- Substitute the width [tex]\( k + 3 \)[/tex] and the length [tex]\( k - 9 \)[/tex] into the perimeter formula:
[tex]\[ P = 2((k - 9) + (k + 3)) \][/tex]

4. Simplify Inside the Parentheses:
- Combine like terms inside the parentheses:
[tex]\[ (k - 9) + (k + 3) = k + k - 9 + 3 = 2k - 6 \][/tex]

5. Multiply by 2:
- Now multiply the simplified expression by 2 to find the perimeter:
[tex]\[ P = 2(2k - 6) = 4k - 12 \][/tex]

Therefore, the expression that represents the perimeter of the rectangle is:

[tex]\[ \boxed{-12 + 4k} \][/tex]

This matches one of the provided answer choices exactly.