Question

which point could be removed in order to make it the relation a function? (-4, 3) (-5, 6) (1, 0) (-4, 5) (9, 5) (0, -7)

Answer 1

In a function, each input (x-) value has exactly one output (y-) value. That's not the case here, where we have (-4,5) and (-4,3) (two different y-values for one x-value). Eliminating either (-4,5) or (-4,3) will make this relation into a function.

Answer 2

(-4, 5)

Because the -4 for x was used already