To find the domain and the range from the graph of a function, we consider perpendicular projections of the graph to the x-axis and to the y-axis.
The projection to the x-axis is the Domain (the orange line segments), and the projection to the y-axis gives us the Range (the yellow line segments).
20.
Domain: [-6, -1) ∪ (-1, 4] Range: (-3, 5]
21
Domain: [-5, -2)∪(-2, 2)∪(2, 7] Range: [-3, 5]
22.
Domain (-5, 3], Range: {1}
23.
Domain: (-5, 4], Range: [-3, 4]
