How would you describe domain

The domain represents the x-axis, more specifically, what is happening on the x-axis. So when looking at a graph, if you are asked to find the domain think about what the x-axis looks like. I put an image in to show you an example of what the domain would be for a parabola:

So on the left side of the x-axis, we can see that the line stretches out into negative infinity, so the domain would begin at negative infinity.

On the right side of the x-axis, the parabola also stretches into positive infinity, so here the domain would be (negative infinity, positive infinity), because it goes to both ends forever.

could you reply to this with the question so i can ?