The first step that we must take to solving this problem is to fully understand what the problem statement is asking from us and what is given us to solve the problem. Looking at the problem statement, we can see that they are asking us to determine what the domain of the function is in the graph that was provided. However, first of all, let us define what domain is.
- Domain ⇒ Domain is what x-values can be used in the function that is graphed. For example, if a line just goes side to side all the way to negative and positive infinity, then the domain would be negative infinity to positive infinity as it includes all of the x-values in it's solutions.
Looking back at our problem, we can see that this is similar to the example that was provided in the definition. We can see that the parabola reaches out to both positive and negative infinity in the x-direction but at a slope. Although we can only see it reach -2 and 6 we know that the parabola continues going on even after that.
Therefore, looking at the options that were provided option D, -∞ < x < ∞ would be the best fit as it showcases that x reaches from negative infinity to positive infinity.
