Hello! When finding the perimeter of a rectangle, you have to consider the properties of a rectangle. A rectangle has two pairs of equal sides where one is the width, while the other one is the length. Now looking back at your question, it says "... a rectangle that is x units wide" ⇒ you let the width = x ; this is the same with "y units long" ⇒ length = y. Perimeter can just be : P = 24. Therefore, The equation would be: x + x + y + y = P. 2x + 2y = P. (Sub in P = 24) ∴ 2x + 2y = 24. (This should be your answer.) :) Good luck (Message me if you have any problem)