### Home > CC3MN > Chapter 9 > Lesson 9.1.3 > Problem9-42

9-42.

Identify which of the relationships shown below is not a function. Explain your reasoning.

1.  $x$ x column 1 $3$ x column 2 $8$ x column 3 $1$ x column 4 $9$ x column 5 $–1$ x column 6 $0$ $y$ y column 1 $12$ y column 2 $4$ y column 3 $0$ y column 4 $4$ y column 5 $–3$ y column 6 $–8$
2.  $x$ x column 1 $5$ x column 2 $2$ x column 3 $–1$ x column 4 $0$ x column 5 $–15$ x column 6 $2$ $y$ y column 1 $2$ y column 2 $0$ y column 3 $–11$ y column 4 $8$ y column 5 $–25$ y column 6 $1$

A relationship is a function only if there is no more than one $y$-value for each $x$-value. Check the $x$-values in both tables to see to find any that appear multiple times. When you find a value for $x$ that appears multiple times, check the corresponding $y$-values. If the $y$-values are different, then the relationship is not a function.

Relationship (b) is not a function. When $x$ equals $2$, $y$ can equal $0$ or $1$.