1. 4.2 Graphing a Function Rule HW: 4.2
What you need:
Bell Work
4.1 Homework
Math Notes
Don’t Forget, you can do test corrections if you want a better grade!
HW: 4.2

2. Bell Work Draw a graph for the following story:
Garrett waited three minutes before starting to fill the bathtub, but after two minutes of adding water to the tub, he decided to drain the water.

3. Graphing a Function Rule
Lesson 4.2

4. Objective: Each student will be able to GRAPH a function rule

5. Function Rule Function Rule start with the input number
perform an operation,
get an output number.

6. Function Machine
Function Rule
Input
Output

7. Words to Know Domain = x (input values) Range = y (output values)
When you put x and y together they become an Ordered Pair.
Ordered Pair: (input, output)

8. You Tube Video

9. Function Table
You can organize the input numbers, output numbers, and function rule in a function table.
What does this look like?

10. Function Table 1 2 x + 1 Input x Function rule x + 1 Output y 1
(1) + 1 2
x + 1 1 2

11. Function Table 2 3 x + 1 Input x Function rule x + 1 Output y 1
(1) + 1 2
(2) + 1 3
x + 1 2 3

12. Function Table 4 3 x + 1 Input x Function rule x + 1 Output y 1
(1) + 1 2
(2) + 1 3
(3) + 1 4
x + 1 3 4

13. Ordered Pairs
When we find 3 or 4 inputs and outputs we make ordered pairs
Input x
Function rule
x + 1
Output y 1
(1) + 1 2
(2) + 1 3
(3) + 1 4
(1, 2)
(2, 3)
(3, 4)

14. Partner Talk Right Partner Left Partner
1. What variable goes with input?
2. What is an ordered pair?
Left Partner
1. What variable goes with output?
2. What variable goes with domain? What about range?

15. Example 1
Function rule
Input
Output
Make a function table and graph the equation.
y = x -3
Ordered pairs =
(1, -2) (0, -3) (-1,-4)
(-2, -5) x
X-3 y 1
1 - 3 -2
0 - 3 -3
-1 - 3 -1 -4 -2
-2 - 3 -5

16. (1, -2)
(-1, -4)
(0, -3)
(-2, -5)

17. Example 2
Function rule
Input
Output
Make a function table and graph the equation.
y = 2x
Ordered pairs =
(1, 2) (2, 4) (3,6)
(4, 8) x 2x y 1
2(1) 2 2
2(2) 4
2(3) 3 6 4
2(4) 8

18. (4, 8)
(3, 6)
(2, 4)
(1, 2)

19. Example 3
Function rule
Input
Output
Make a function table and graph the equation.
y = 2x -1
Ordered pairs =
(1, 1) (2, 3) (3,5)
(4, 7) x
2x -1 y 1
2(1)-1 1 2
2(2)-1 3
2(3)-1 3 5 4
2(4)-1 7

21. Your Turn Make a function table and graph the equation. y = -3x
Inputs: (2, 3, 4, 5)

22. Challenge
Function rule
Input
Output x y -2 -1 1 2

23. Quick Review 1. What is an ordered pair? (input, output)
2. How do you find the range, if you are given the domain?
Plug in the domain values to find the range.
3. A set of inputs can also be called?
Domain
4. A set of outputs can also be called?
Range