Question

Question 6b

6b of 6
The width of a rectangle is 15 centimeters less than its length. If the area of the
rectangle is 100 square centimeters, find the length and the width using the formula
A = lw.
O Length = 25 centimeters and Width = 10 centimeters
○ Length = 20 centimeters and Width = 5 centimeters
O Length = 115 centimeters and Width = 100 centimeters
○ Length = 5 centimeters and Width = 20 centimeters

Answer 1

○ Length = 20 centimeters and Width = 5 centimeters

Explanation:

Let the length = L

Then the width is L - 15

A = lw

100 = L(L - 15)

L² - 15L - 100 = 0

(L - 20)(L + 5) = 0

L - 20 = 0 or L + 5 = 0

L = 20 or L = -5

Since a length of a rectangle cannot be negative, we discard the solution L = -5 and keep the solution L = 20.

L = 20

width = L - 15 = 20 - 15 = 5

Answer: ○ Length = 20 centimeters and Width = 5 centimeters