Question

Is this a function?
{(2, 4), (2,5), (2,6), (2,7)}

Answer 1

No

Explanation:

For a relation to be a function it must have a unique x-value for every y-value. This means that in a function x-values cannot repeat. In this relation, the x-value repeats multiple times, so it is not a function. It is also a vertical line, and vertical lines can never be functions since the x-value is constant and therefore repeats.