Part B, for x is not equal to zero, express f prime of x as a piecewise defined function. Find the value of x for which f prime of x is equal to negative 3. So the first thing you might be wondering is why did we even have to take out x is equal to zero from the, or why is the derivative not going to be defined there? And that's just because you're going to see that the derivative is going to be something different when we approach x is equal to zero from the left versus when we approach x is equal to zero from the right. And that's why they just took it out of there for us. So let's just figure out what that derivative is for all the other values of x. So f prime of x is equal to, so for x is less than zero, we're going to take the derivative of this first case.