Name
Reteaching
15-6
Functions
Is the relation a function?
Example A
x
y
In Example A, there is only one y-value for
each x-value. The relation is a function.
In Example B, two y-values, 3 and 0, are
assigned to the x-value, !1. So, the relation
is not a function.
Example B
x
y
!3
1
!1
3
!2
2
!2
!1
!1
3
0
1
0
4
!1
0
The ordered pairs and graphs show there is only one y-value for each x-value.
Function
Another Function
The graph of a function may be a
straight line.
6
5
4
3
2
1
The graph of a function is not always a
straight line.
Z
0
6
5
4
3
2
1
Y
0
1 2 3 4 5 6
Ordered pairs: (0, 0), (2, 1), (4, 2) Another
Y
1 2 3 4 5 6
Ordered pairs: (0, 0), (2, 2), (4, 2), (6, 3)
Tell whether each relation shown in the table is a function.
1.
4.
x
y
5
6
2.
x
y
2
0
3
0
7
4
8
5
3.
x
y
1
!5
10
2
!2
4
2
4
0
0
4
6
3
!6
Writing to Explain Explain how graphing the ordered pairs of a relation can help you
decide if the relation is a function.
© Pearson Education, Inc. 6
Reteaching 15-6
Z
56
Topic 15
Name
Reteaching
15-6
Functions
Is the relation a function?
Example A
x
y
In Example A, there is only one y-value for
each x-value. The relation is a function.
In Example B, two y-values, 3 and 0, are
assigned to the x-value, !1. So, the relation
is not a function.
Example B
x
y
!3
1
!1
3
!2
2
!2
!1
!1
3
0
1
0
4
!1
0
The ordered pairs and graphs show there is only one y-value for each x-value.
Function
Another Function
The graph of a function may be a
straight line.
6
5
4
3
2
1
The graph of a function is not always a
straight line.
Z
0
6
5
4
3
2
1
Y
0
1 2 3 4 5 6
Ordered pairs: (0, 0), (2, 1), (4, 2) Another
Y
1 2 3 4 5 6
Ordered pairs: (0, 0), (2, 2), (4, 2), (6, 3)
Tell whether each relation shown in the table is a function.
1.
x
y
5
3.
x
y
x
y
2
0
1
!5
10
6
3
0
2
!2
4
7
4
2
4
0
0
8
5
4
6
3
!6
Function
4.
2.
Not a Function
Function
Writing to Explain Explain how graphing the ordered pairs of a relation can help you
decide if the relation is a function.
Sample answer: After I graph the ordered pairs
of a realtion, I can look at the graph to see if
each x-value has only one y-value. If any x-value
has more than one y-value, it’s not a function.
56
Topic 15
© Pearson Education, Inc. 6
Reteaching 15-6
Z