Question

Graph the relation shown in the table. Is the relation a function? Why or why not?
(-5,20)
(-1,4)
(2,-5)
(4,-1)

No; a horizontal line passes through two graphed points.

Yes; no vertical line passes through two graphed points.

Yes; no horizontal line passes through two graphed points.

No; a vertical line passes through two graphed points.

Answer 1

The relation is a function because no vertical line passes through two graphed points.

Here is the graph of the points (-5,20), (-1,4), (2,-5), and (4,-1):

(see graph: https://www.desmos.com/calculator/yneurhw7xz)

As you can see, each input (x-value) corresponds to only one output (y-value), which means the relation is a function.