Only zero will be equal to zero when you take it to the fourth power. So one way we could say this is going to be true for any non-zero x, or we could just say x does not equal zero. And this is a little bit more straightforward. We add five to both sides, we get two x is less than five. Divide both sides by two, you get x is less than 5 1⁄2. So it might be tempting to say, all right, the intervals that matter are all the x's less than 5 1⁄2, but x cannot be equal to zero. Now, is that the entire interval where our function is decreasing?