Two times negative six is negative 12 or minus 12x, and the derivative of 12x is plus 12. And let's see, you can factor out a three here, so it's three times x squared minus four x plus four, and this part is indeed equal to x minus two squared, so this is equal to three times x minus two squared. So her step one looks right on target. Okay, step two, the solution of h prime of x is equal to zero is equal to x equals two. Yeah, that works out. If you were to say three times x minus two squared, which is h prime of x, the first derivative, and set that equal to zero, this is going to be true when x is equal to two. And so any point where your first derivative is equal to zero or it's undefined, it is indeed a critical point.