This really isn't so much of a question as it is wanting some people's opinions. We're probably all familiar with the Law of Cosines (and I'm working on a website page about it.)
If you look at the attached graphic, it shows the Law of Cosines as it is printed in just about every textbook, website, blackboard, etc. (Choice A)
Why isn't it presented differently, such as it is in choice B)?
For one thing that is a rather awkward way to state an equation. Don't we ALWAYS have the quantity for which we are solving, alone; by itself; and on the left side of an equation? Heck, we NEVER see Einstein's equation written as c = square root [ Energy / mass}.
So, why is the Law of Cosines stated in such an awkward, clumsy way?