Question

Use the vertical line test to determine whether the graph is the graph of a function.

Answer 1

Do you know why?

Answer 2

this is an eyeball problem. check to see if any vertical line crosses the graph at more than one point. if it does, that means that the x - value of that line corresponds to more than one y - value so you do not have a function

Answer 3

since a function can only have a single value (not more) for every input, by definition; so if you draw a vertical line and it hits more than one value, you have violated the definition of function and the graph can not represent a function in that case