Math problem help please???

Question

the lenght of a certain rectangle is twice it's width. if the lenght is decreased by three centimeters, the area of the resulting rectangle is twelve square centimeters less than the area of the original rectangle. find the original dimensions of the rectangle. please show step by step

Answer 1

let 'l' be the length and 'b' be breadth

given : l=2b

            (l-3)(b)=lb-12

=> (2b-3)(b)=2b^2-12

=>2b^2-3b=2b^2-12

=>b=4 , l=8

Answer 2

The same thing that the guy said on top of me.

Answer 3

w=2l

(w-3)l=wl-12

width=4

length=8