You say, well, you know, this isn't fair. This isn't a differential equations class. And the thing to keep in mind is, if on an AP exam you see differential equations, they're really asking you to solve a differential equations that can be solved using the skills that you would learn in an AP class. And the main differential or class of differential equations that you could solve are the ones, are separable differential equations. The ones where you can separate the independent and the dependent variables. And if you don't have any idea of what I'm talking about, I'm about to show you. So, let me rewrite this differential equation.