Answer: L = 10 , W = 14
Explanation:
Let
represent the Length and
represents the Width , then from the first statement , we have

That is :

The formula for finding the area of a rectangle is given as:
x Width
That is :

140 =


That is :

solving the quadratic equation , we have
or

Since the length can not be negative , therefore :
L = 10
Substitute L = 10 , to get W ,
W = 2L - 6
W = 20 - 6
W = 14
Therefore , the dimension is 10 x 14