Which relation is a function?

{(2, 4), (2, -7), (2, 11), (2, -15)}

{(-1, 3), (5, 3), (-6, 7), (9, 0)}

{(0, -7), (4, -8), (0, -9), (4, -10)}

{(6, 0), (-7, 14), (-2, -5), (-2, 5)}

Question

Which relation is a function?

       {(2, 4), (2, -7), (2, 11), (2, -15)}

       {(-1, 3), (5, 3), (-6, 7), (9, 0)}

       {(0, -7), (4, -8), (0, -9), (4, -10)}

       {(6, 0), (-7, 14), (-2, -5), (-2, 5)}

tkhunny · Answer

If there are NO repeats in the x-values, it is a function.

(0,4), (1,3) - Function

If there ARE repeats in the x-values, the y-values better be the same or it isn't a function.

(0,4), (0,5) - Not a function

abb0t · Answer

You can also plot these points and see if it passes the vertical line test. This might be a bit tedious, but if you forget the definition, then you can also do this.

anonymous · Answer

B