It is not a function, it does not pass the vertical line test. The x values have multiple outputs. For example, 5 has an output of 5 and of 10. Therefore it can't be considered a function.
If any of your x's repeat (aka 5) then it is not a function. Because in order to be a function you cannot have any of the x's repeat or an x value has more than 1 y value. Hope this helped!<3
