Question

Without graphing, how do you figure out points to an equation that isn't a function ?

Answer 1

Are you asked if you can either prove or disprove it being a function, or are you only asked to show it’s not a function, because it’s definitely possible to express y as a function of x here.

Answer 2

The main thing with a function is that every x coordinate maps to exactly 1 y coordinate. For an equation to not have a function, it means that there are two (or more) different y values that share the same x value.

So find some value of x you can input which results in two or more possible solutions for y.