This is the case if we're getting very positive x's, very positive infinity direction, or very negative. It's still the absolute value of those x's that are very, very, very large as we approach positive infinity or negative infinity. Well, in the numerator we only have one term. We have this x term. But in the denominator we have two terms under the radical here. And as x gets larger and larger and larger, either in the positive or the negative direction, this x squared term is going to really dominate this one. You can imagine when x is a million, you're going to have a million squared plus 1.