Question

determine if the relation is a function (2,3),(-1,4),(4,6),(5,6)

Answer 1

It is a function because there are no repeated X values

Answer 2

Make sure that it passes the "vertical line test" when graphed, meaning no vertical line on a graph can pass through two points on the potential function. For example, in a quadratic function, you get a parabola on your graph, and no matter what vertical line you use, it will never pass through 2 points on the graph.