Finding length and width with a word problem.

Question

The length of a rectangle is 5 yd more than double the width. And the area of the rectangle is 42 yd ^2 . what are the dementions

Answer 1

Width = W

 

Length = 2W + 5

 

Area = 42 = W(2W+5) = 2W^2 +5W

 

Set the quadratic equal to 0

 

2W^2+5W-42 = 0

 

We can factor 

 

(2W - 7  )(W + 6) = 0

 

W = -6 is thrown out because it is negative

 

W = 7/2 is the answer for the width

 

and the length is twice that plus 5

 

2(7/2)+5 = 7+5 = 12

 

Length = 12

Width = 7/2 =3.5