The correct is:
[tex][(-9,3),\:(-5,1),\:(7,-5),\:(4,3)][/tex]
The definition of a function is that for every value of [tex]x[/tex] we get one from [tex]y[/tex].
In the first appears [tex](-6,1)[/tex] y [tex](-6,-7)[/tex], it is not a function, since it does not meet the definition given above, there can only be one value for x, if there are [tex]2[/tex] or more, called relation.
In 2 repeat: [tex](7,-6)[/tex] and [tex](7,0)[/tex]
In 3 repeat: [tex](1,-3)[/tex] and [tex](1,0)[/tex]
