Question

Decide whether the relation is a function.
{(1,-6),(1,-9),(4,-9),(9,-7),(10,-8)}

Answer 1

use vertical line test

Answer 2

@joanna601 -- Do you know the definition of a function? Without that, it's hard to explain the correct answer.

Answer 3

Plot your points, If your vertical line does not cross 2 points then it is a function

Answer 4

those 2 points pass the vertical line test

Answer 5

@manfrom3004 -- Your observation means the relation (which may or may not be a functio) does not have an inverse -- it is not one-to-one.

Answer 6

It's not a function, think of a soda machine. If there is one button (x) for two items (y) that wouldnt make sense, so it not a function.

Answer 7

Sorry, about that... haven't slept in days. Anyways... same thing, except with (1,-6) and (1,-9). They have same x coordinate. Thus, not a function.