So let's see where our numerator can be equal to 0 for the second derivative. So let's set the numerator of the second derivative. 27 times 12 x squared minus 4x to the 6th is equal to 0. Remember, that's just the numerator of our second derivative. Any x that makes the numerator 0 is making the second derivative 0. So let's factor out a 4x squared. Now we'll have 27 times, if we factor a 4 out of the 12, we'll just get a 3, and we factored out the x squared, minus, we factored out the 4, we factored out an x squared, so we have x to the 4th is equal to 0.