So derivative of t to the third with respect to t is three t squared. If that's unfamiliar, I encourage you to review the power rule. The derivative of negative four t squared with respect to t is negative eight t, and derivative of three t with respect to t is plus three. Derivative of a constant doesn't change with respect to time, so that's just zero. And so here we have velocity as a function of time, and so if we wanna know our velocity at time t equals two, we just substitute two wherever we see the t's, so it's gonna be three times four, three times two squared, so it's 12 minus eight times two, minus 16, plus three, which is equal to negative one. And you might say, well, negative one by itself doesn't sound like a velocity. Well, if they gave us units, if they told us that x was in meters and that t was in seconds, well, then x would be, well, I already said, would be in meters, and velocity would be negative one meters per second.