First, domain refers to the x axis. So you would find the lowest number on the X axis, -2, and then you look at the kind of dot on that number. It is an open dot, which means that it is all the numbers up to -2, but does not include -2. Then you find the highest number, in this case 2. Looking at the dot that is marking it, it is a closed dot, meaning it includes the number 2. So the domain would be numbers between -2 and 2, but does not include -2. all numbers greater than -2, x, all numbers less than and equal to 2.
