Hey there!
To find the domain of a graph, you look for the points furthest to the left and furthest to the right. For example, you could have the points (-3,-4) and (9,10). When looking for the domain, you only focus on the x-values. Therefore, your domain would be (-3,9).
To find the range, you find the highest and lowest points on the graph, and look for the y-values. Say the (-3,-4) and (9,10) are also the lowest and highest points on your graph. Therefore, your range would be (-4,10)
I hope this explanation helps!
