If you’re looking for quadratic function information, check out our guides on finding the inverse and finding the max or min.
Take the left value (the x value) of each ordered pair and place them vertically in the left column (input) of a 2 column table. Repeat for the right values (the y values), placing them in the right column (output).
(1, 2) (2, 4) (3, 10) (1, 7) (5, 0)
(1, 2) (2, 4) (3, 10) (4, 10) (5, 0)
In other words, if two or more points have the same X value and different Y values, the relation is not a function. The relation is a function if you move the vertical line across the graph without hitting two or more points at the same time.
