Determine if the relation y=4x−1 is a function by first graphing the relation, then applying the vertical line test. Enter 1 if the relation is a function. Enter 2 if the relation is not a function.

Answer 1

We first graph the relation y=4x−1 by making a table of values and plotting the points:

| x | y |
|---|---|
| -3 | -13 |
| -2 | -9 |
| -1 | -5 |
| 0 | -1 |
| 1 | 3 |
| 2 | 7 |
| 3 | 11 |

The graph looks like:


We can now apply the vertical line test: if any vertical line intersects the graph at more than one point, then the relation is not a function. If every vertical line intersects the graph at most once, then the relation is a function.

In this case, we see that every vertical line intersects the graph at most once, so the relation is a function. Therefore, we enter 1.