Answer: The length is 9 inches.
Explanation:
- L = 3w - 6 (the length is 6 less than 3 times the width).
- 28 = 2(3w - 6) + 2w (plug in width and length --> multiplied by 2 because of perimeter).
- 28 = 6w - 12 + 2w (distribute)
- 28 = 8w - 12 (combine like terms)
- 40 = 8w (add 12 to both sides)
- 5 = w <-- width
Find the length:
- L = 3w - 6
- L = 3(5) - 6
- L = 15 -6
- L = 9 in