So this is negative 16 right over here. So just like that, we have the equation for the line tangent to the graph of h at t is equal to zero. I'll write it one more time. It is, we've got a mini drum roll here, y is equal to negative 16t plus 91. That's the equation of that tangent line right over there. And then they say, we want to use this equation to approximate the internal temperature of the potato at time t equals three. So let's say that this is time t equals three right over here.