Transverse wave equation help?

Sorry if this is posted in wrong sub-reddit, but I would like some help re-arranging this transverse wave equation, so that the subject is L. I'm a musician, not a engineer, and have spent all night trying to give myself a crash course in re-arranging complex equations, but the examples i've seen don't include multiple sets of divisions or brackets. Any help is welcome, even if it's a link to some examples. Cheers