Unit 4 Section 6 Writing a Function Rule.notebook
January 27, 2016
Bell Ringer ­ Solve.
f(x) = 2x + 1
g(x) = ­3x ­ 7
1)
f(g(­2))
2)
f o g(­4)
3)
f(5) + g(­3)
Jan 26­10:33 AM
Example 4:
1 of
each X
Function
non­vertical,
straight line
horizontal
line
y=kx
(origin)
Linear Function Constant Function Direct Variation
a.) f(x) = ­4x
b.) y = 2x + 3
c.) y = x2 ­ 4
d.) y = ­5
e.) x = 3
f.) xy = 7
Jan 26­1:10 PM
1
Unit 4 Section 6 Writing a Function Rule.notebook
January 27, 2016
check homework
1 of
each X
non­vertical,
straight line
horizontal
line
y=kx
(origin)
Feb 4­10:17 AM
Writing a Function Rule
Unit 4
Jan 11­8:35 AM
2
Unit 4 Section 6 Writing a Function Rule.notebook
January 27, 2016
Reminder: Function notation:
f(x) = 2x - 5
Output Values
(dependent variable)
"y"
Input Values
(independent variable)
"x"
Jan 11­8:36 AM
Example 1: Write a function Rule for each table
x
y
x
y
2
3
­4
­6
­8
­10
­1
­3
4
­8
­12
­5
5
­10
­14
­7
6
­12
­16
­9
Jan 11­8:38 AM
3
Unit 4 Section 6 Writing a Function Rule.notebook
January 27, 2016
Example 2: Write a function Rule for each table
x
x
y
y
1
6
1
2
2
8
2
5
3
10
3
8
4
12
4
11
5
14
5
14
Jan 11­8:38 AM
Example 3: Write a function Rule for each table
x
x
2
14
3
­8
­12
­2
­3
18
4
­16
­4
22
5
­20
­5
26
6
­24
­6
30
Jan 11­8:39 AM
4
Unit 4 Section 6 Writing a Function Rule.notebook
January 27, 2016
Example 4: A car is 30 times longer than its scale model.
Write a function rule to describe the relationship.
a.)
b.)
If the model is 6 in long, how long is the car?
c.)
If the car is 60 in wide, how wide is the model?
Jan 11­8:39 AM
Example 5: You invest $209 to buy shirts and then sell them for $9.50
each.
a.) Write a function rule to determine your profit.
b.)
Use your rule to find profit after selling 24 shirts.
c.)
How many shirts do you need to sell to get back your investment?
Jan 11­8:39 AM
5
Unit 4 Section 6 Writing a Function Rule.notebook
January 27, 2016
Example 6: Write a function rule to represent each situation.
A) the amount of your friend's allowance if the amount she receives is
$2 more than three times the amount you receive
B) the price p of a pizza is $6.95 plus $.95 for each topping t on the
pizza
C) A new book is being planned. It will have 24 pages of introduction.
Then it will have c 12-page chapters and 48 more pages at the end. Write
a rule that represents the total number of pages p in the book as a
function of the number of chapters. Suppose the book has 25 chapters.
How many pages will it have?
Dec 30­11:32 AM
Keystone Ready
The table below shows values of y as a
function of x.
x
y
2
10
6
25
14
55
26
100
34
130
Which linear equation best describes the
relationship between x and y?
A. y = 2.5x + 5
B. y = 3.75x + 2.5
C. y = 4x + 1
D. y = 5x
Feb 19­7:18 PM
6
Unit 4 Section 6 Writing a Function Rule.notebook
January 27, 2016
Feb 19­7:20 PM
7