Now, is that the entire interval where our function is decreasing? Well, let's think about what happens at zero itself. We're decreasing over the interval from negative infinity all the way up to zero, and we're also decreasing from zero to 5 1⁄2. And so if we're decreasing right to the left of zero, we're decreasing right to the right of zero, we're actually going to be decreasing at zero at, we're also going to be decreasing at zero as well. So there's something interesting here. Even though the derivative at x equals zero is going to be equal to zero, we are still decreasing there. And so the interval that we care about, the interval over which we're decreasing is just x is less than 5 1⁄2.