This says, look, I wanna take the derivative of whatever is inside of the parentheses with respect to x. So the derivative of f with respect to x, we could use a notation that that is just f prime of, f prime of x. And that is going to be equal to, now here we can use our derivative properties. The derivative of the sum or difference of a bunch of things is just the derivative of, is equal to the sum or the difference of the derivative of each of them. So this is equal to the derivative, let me just, it's the derivative with respect to x of each of these three things. So the derivative with respect to x, actually let me just write it out like this, of that first term, plus the derivative with respect to x of that second term, minus the derivative with respect to x of that third term, of that third term. And I'll color code it here.