Question

The area of a rectangle is 42 m2, and the length is

8 m less than two times the width. Find the
dimensions of the rectangle.

Answer 1

length = 14 m

width = 7 m

Explanation:

l = length

w = width

l = 2w - 8

w(2w - 8) = 42

2w² - 8w - 42 = 0

you can factor out a 2 to work with smaller numbers:

w² - 4w - 21 = 0

(w - 7)(w + 3) = 0

w = 7

'w' cannot equal a negative so we discount it as an answer

find length:

l = 2(7) - 8

l = 14 - 8 or 6m