CPM Homework Help : CC3MN Problem 9-42

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

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

Hint:

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.

Answer:

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

$x$	$5$	$2$	$–1$	$0$	$–15$	$2$
$y$	$2$	$0$	$–11$	$8$	$–25$	$1$

$x$	$3$	$8$	$1$	$9$	$–1$	$0$
$y$	$12$	$4$	$0$	$4$	$–3$	$–8$