Our second derivative, this looks like it'll get a little bit hairier. So our second derivative is the derivative of this. So it's equal to, we can now use the product rule, it's the derivative of this first expression times the second expression. So the derivative of this first expression, 3 times 4 is 12. 12x squared, we just decrement the 3 by 1, times the second expression, times x to the fourth plus 27 to the minus 1. And then to that we want to add just the first expression, not its derivative, so just 4x to the third, times the derivative of the second expression. So the second expression, we could take the derivative of the inside, which is just 4x to the third, this derivative of 27 is just 0.