Question

The length of a rectangle is 3 m less than twice the width, and the area of the rectangle is 14 m2 . find the dimensions of the rectangle.

Answer 1

Let W = width and L = length  length is 3 less than twice width  ==>  L = 2*W - 3 Area = L*W = (2*W-3)*W = 14 
2*W^2 -3*W - 14 = 0
(2W - 7)*(W + 2) = 0 
2W - 7 = 0  or  W + 2 = 0
W = 7/2  or  W = -2
Width cannot be negative so W = 7/2 = 3.5
So L = 2*(7/2) - 3 = 7 - 3 = 4 The length is 4 m and the width is 3.5 m   Check:  2*(3.5) - 3 = 4, length is 3 less than twice width
 
Area = L*W = 4*3.5 = 14 m^2