So, the first derivative, the rate of change of acceleration is going to be equal to, so this is negative six t plus 12. Now let's think about when does this thing equal zero? Well, if we subtract 12 from both sides, we get negative six t is equal to negative 12. Divide both sides by negative six, you get t is equal to two. So, a couple of things, you could just say, alright, look, I know that this is a downward opening quadra, parabola right over here, I have a negative coefficient on my second degree term. I know that the slope of the tangent line here is zero at t equals two, so that's gonna be my maximum point. Or you could go a little bit further, you could take the second derivative, you, let's do that, just for kicks.