So the derivative of this whole thing with respect to this inside expression is going to be times 1 over x to the fourth plus 27. If you found that confusing, you might want to re-watch the chain rule videos. But that's the first derivative of our function. And I could rewrite this, this is equal to 4x to the third over x to the fourth plus 27, or I could write it as 4x to the third times x to the fourth plus 27 to the negative 1. All three of these expressions are equivalent. I'm just writing, I've multiplied it out, or I could write this as a negative exponent, or I could write this as a fraction with this in the denominator. They're all equivalent.