Question

Which of the following does not represent a function?
Answer

x 1 3 5 7
y 7 11 15 11

x -4 -3 -2 -1
y -32 -18 -8 -2

x -3 2 6 2
y 0 1 5 4

x -4 -2 0 2
y 3 -1 -5 -9

Answer 1

The requirement of a [well-defined] function is that there is exactly one (not necessarily unique) y-value for each x-value. If you have more than one y-value for an x, then its not a function.

Answer 2

it is not a function if 1 x value is paired with 2 different y values....