OK, your first one is right on.
For the next two, just take the derivative of the derivative, then take the derivative of that!
Remember,
Let's go back to the first derivative (I didn't see this the first time)
Remember to reduce! You can pull an 8 out of there to get .
Either way, your answer is technically right.
I want you to simplify it, then post back with that.
After that, you should go ahead and take another derivative.