Look at the values on the axes of the graph.
Explanation:
Domain can be found by looking at the x-axis of a graph. Range can be found by looking at the y-axis of a graph. You have to find at what point on the axis is the graph stopping.
For example, if I wanted the domain of y=x, I would say it is all real numbers. Why? Because when we look along the x-axis, from left to right, we can see that it continues going until infinity. That means that there are no stopping points in the graph of y=x.