Relations and Function Independent Practice

Directions: Determine if each relation below represents a function and explain why.

1.
\begin{tabular}{|c|c|}
\hline
[tex]$x$[/tex] & [tex]$y$[/tex] \\
\hline
3 & 9 \\
\hline
8 & 7 \\
\hline
12 & 5 \\
\hline
15 & 3 \\
\hline
\end{tabular}

Is this a function? Why? [tex]$\qquad$[/tex]

2. Is this a function? Why? [tex]$\qquad$[/tex]

3. [tex]$\{(8,5),(7,7),(6,9),(5,11)\}$[/tex]

Is this a function? Why? [tex]$\qquad$[/tex]

4. Is this a function? Why? [tex]$\qquad$[/tex]

5. Is this a function? Why? [tex]$\qquad$[/tex]

6.
\begin{tabular}{|c|c|c|c|c|c|}
\hline
[tex]$x$[/tex] & 1 & 2 & 3 & 2 & 1 \\
\hline
[tex]$y$[/tex] & 12 & 8 & 5 & 3 & 2 \\
\hline
\end{tabular}

Is this a function? Why? [tex]$\qquad$[/tex]

7. Is this a function? Why? [tex]$\qquad$[/tex]

8. [tex]$\{(8,5),(6,6),(4,7),(2,8)\}$[/tex]

Is this a function? Why? [tex]$\qquad$[/tex]

9. Is this a function? Why? [tex]$\qquad$[/tex]

10. [tex]$\{(1,7),(0,5),(1,3),(2,1)\}$[/tex]

Is this a function? Why? [tex]$\qquad$[/tex]

11.
\begin{tabular}{|c|c|}
\hline
[tex]$x$[/tex] & [tex]$y$[/tex] \\
\hline
-1 & 6 \\
\hline
0 & 5 \\
\hline
1 & 6 \\
\hline
2 & 5 \\
\hline
\end{tabular}

Is this a function? Why? [tex]$\qquad$[/tex]

12. Is this a function? Why? [tex]$\qquad$[/tex]



Answer :

Let's evaluate each given relation to determine if they represent functions.

### Explanation:

A relation is a function if for every [tex]\( x \)[/tex] value there is only one corresponding [tex]\( y \)[/tex] value. In other words, no [tex]\( x \)[/tex] value is paired with more than one [tex]\( y \)[/tex] value.

### Solutions:

1. Relation:
[tex]\[ \begin{tabular}{|c|c|} \hline$x$ & $y$ \\ \hline 3 & 9 \\ \hline 8 & 7 \\ \hline 12 & 5 \\ \hline 15 & 3 \\ \hline \end{tabular} \][/tex]
Is this a function? Yes

Why? Each [tex]\( x \)[/tex] value in the relation (3, 8, 12, 15) maps to exactly one [tex]\( y \)[/tex] value. They are all unique and do not repeat.

2. Relation:
[tex]\[ \{(8,5),(6,6),(4,7),(2,8)\} \][/tex]

Is this a function? Yes

Why? Each [tex]\( x \)[/tex] value in the set (8, 6, 4, 2) maps to exactly one [tex]\( y \)[/tex] value. There are no duplicate [tex]\( x \)[/tex] values with different [tex]\( y \)[/tex] values.

3. Relation:
[tex]\[ \{(8,5),(7,7),(6,9),(5,11)\} \][/tex]

Is this a function? Yes

Why? Each [tex]\( x \)[/tex] value in the set (8, 7, 6, 5) maps to exactly one [tex]\( y \)[/tex] value. There are no duplicate [tex]\( x \)[/tex] values with different [tex]\( y \)[/tex] values.

4. Relation:
[tex]\[ \{(1,7),(0,5),(1,3),(2,1)\} \][/tex]

Is this a function? No

Why? The [tex]\( x \)[/tex] value 1 is associated with both 7 and 3, violating the rule that each [tex]\( x \)[/tex] value must map to exactly one [tex]\( y \)[/tex] value.

5. Relation:
[tex]\[ \begin{tabular}{|c|c|} \hline$x$ & $y$ \\ \hline-1 & 6 \\ \hline 0 & 5 \\ \hline 1 & 6 \\ \hline 2 & 5 \\ \hline \end{tabular} \][/tex]

Is this a function? Yes

Why? Each [tex]\( x \)[/tex] value in the table (-1, 0, 1, 2) maps to exactly one [tex]\( y \)[/tex] value. They are unique and do not repeat.

6. Relation:
[tex]\[ \begin{tabular}{|c|c|c|c|c|c|} \hline$x$ & 1 & 2 & 3 & 2 & 1 \\ \hline$y$ & 12 & 8 & 5 & 3 & 2 \\ \hline \end{tabular} \][/tex]

Is this a function? No

Why? The [tex]\( x \)[/tex] values 1 and 2 each appear more than once with different [tex]\( y \)[/tex] values (1 maps to both 12 and 2, and 2 maps to both 8 and 3), which means that it does not satisfy the condition of having each [tex]\( x \)[/tex] value map to exactly one [tex]\( y \)[/tex] value.

### Summary:

1. Relation 1: Yes
2. Relation 8: Yes
3. Relation 7: Yes
4. Relation 10: No
5. Relation 11: Yes
6. Relation 6: No

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