ok. First of all, i am puzzled how you make the equation look so perfect, I can tell that you are not typing this. If anyone can tell me how to make numbers, and variables look like that, it would be appreciated. Ok, on to the problem.

So, you have to isolate L.

First, Multiply the whole Equation by the denominator of the fraction on the left, and you recieve:

next, divide by 5W, and you will recieve:

next. Make everything to the fourth root, so you cancel out that exponent 4. You get:

You cannot have any roots in the denominator. So, you multiply the denominator by 5W(to the fourth root) and you multiply 384EIA(to the fourth root) by 5W(to the fourth root). You get:

Please excuse me if I made a mistake, or if the work isn't clear(which probably isn't). If someone can tell me how to get the thing that allows me to show my work neatly, that would be helpful.