And then it looks like Robert's trying to rewrite it. So we have the negative 2 9ths still. But then he recognized that this is the same thing as x to the 5 3rds in the denominator. And x to the 5 3rds is the same thing as x, as the cube root of x to the 5th. So this is all looking good. Step one looks good. And then step two, it looks like he's trying to find the solution, or he's trying to find x values where the second derivative is equal to zero.