Question

PLZ HELP!!! Which of the following does not represent a function?

Answer 1

It should be the 3rd one
A function can only have ONE answer
E.g. y = a (correct)
y = +/-a (incorrect)

Answer 2

It's the ellipse (3rd one). Why it's not a function?

If you draw a vertical line and if this line intercepts the figure in more than one point, then this figure doesn't represent a function (but a relation instead)