Answer:
a) discrete
b) D: {1, 2, 3}; R: {3, 4}
c) is a function
Step-by-step explanation:
When the graph is made up of individual dots, it represents a discrete function.
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The domain is the set of x-coordinates of the points on the graph:
domain: (1, 2, 3}
The range is the set of y-coordinates of the points on the graph:
range: {3, 4}
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No vertical line intersects the graph in more than one place, so the graph is a function.