So one way, let's say I want to get all the y's and d y's on the left hand side, and all the x's and d x's on the right hand side. Well I can multiply both sides times y. So I can multiply both sides times y. That has the effect of putting the y's on the left hand side. And then I can multiply both sides times d x. I can multiply both sides times d x. And we kind of treat, you can treat these differentials as you would treat a variable when you're manipulating it to essentially separate out the variables. And so this will cancel with that.