Answer: Choice D [tex]-\infty < x < \infty[/tex]
This is another way of saying "the set of all real numbers". This is because there are no restrictions we must place on x. The graph extends infinitely in both left and right directions as the arrows indicate. Any x value can be plugged in to get some y output.
In interval notation, the domain would be written as [tex](-\infty, \infty)[/tex]
