So let's do that. So we get 2 times 8 feet times 4 feet per second plus 2h. So plus 2h is going to be plus 2 times our height right now is 6 times the rate at which our height is changing with respect to t is equal to 0. And so we get 2 times 8 times 4 is 64 plus 12 dh dt is equal to 0. We can subtract 64 from both sides. We get 12 times the derivative of h with respect to time is equal to negative 64. And then we just have to divide both sides by 12.