Question

Which relation is a function?

{(-4,-7), (-9, 5), (4, -2), (-9, 0)}
{(-7, -7), (-2, 5), (−1, 6), (-2, −5)}
{(0, 1), (3, 2), (5, -3), (0, 2)}
{(-3, -2), (-1, 3), (0, -2), (3, 4)}

Answer 1

Here's a little trick I learned in 8th grade. The first numbers don't matter all that matters are the 2nd numbers, and if you have 2 of the same kind of numbers then it's not a function so your answer would be B.