Need to find the perimeter of the box. the lenght of rectangular book is 2 unit less than its width. if the area of the book is 15 unit square.

Area is equal to length x height. Let us say that the height of the book is x, and then the length would be x-2.

Area = length x height

15 = (x-2) x

15 = x^2 - 2x

0 = x^2 - 2x - 15

x = 5

So the length would be (5-2) = 3, and the height would be 5.

The overall perimeter would be 2xlength + 2xheight so 6+10=16.