You can
put this solution on YOUR website!You are doing good so far, except for one little mistake. If the length is twice the width, then

, which changes the second step of your answer to

. This will actually make the problem easier to solve...
Multiply 2 by 2W, and your equation is now

. The step you got lost on is to add the like terms. Since 4W and 2W both have a W on the end, you can add them together to get

. Now solve for W, and you get W=20. Plug this in to L=2W, and you get that L=40.