Which of the following graphs represent a function? Choose all that apply
To determine which graphs represent a function, we need to ensure that each input (or x-value) has only one corresponding output (or y-value). Let's analyze each graph:
Graph 1: 
This graph represents a function since each input has only one corresponding output.
Graph 2: 
This graph does not represent a function since for an input of x = 3, there are two different corresponding outputs (y = 3 and y = 1).
Graph 3: 
This graph represents a function since each input has only one corresponding output.
Therefore, the graphs that represent a function are Graph 1 and Graph 3.