the length of a rectangle is 4 meters less than twice the width. if the area of the rectangle is 240 square meters, find the dimensions

Question

how many meters is the length?

how many meters is the width?

Answer 1

L = 2W - 4

L * W = 240

 

Plug in L.

 

(2w-4)*w = 240

2w^2 - 4w -240 = 0

2(w^2-2w-120) = 0

w^2 - 2w - 120 = 0

(w-12)(w+10) = 0

 

w = 12, -10

 

Since area cannot be negative we know w = 12.  Now solve for L.

 

L  = 2(12)-4

L = 20

 

To check our answer:

 

L*W = 240

20 * 12 = 240

240=240