1. 2-5 writing a function rule
Objective: Write rules for functions from tables and words.
Miss battaglia – algebra 1 cp

2. Warm up
If you wrote the integers 1 to 100, how many times would you write the digit 3?

3. Function notation
To write a rule in function notation, you use the symbol f(x) in place of y.
f(x) = 2x - 5
output values
dependent variable
input values
independent variable

4. Find f(-2), f(0), and f(7) for f(x) = 2x - 5
example
Find f(-2), f(0), and f(7) for f(x) = 2x - 5

5. Write a function rule for each table.x y 1 5 2 6 3 7 4 8 x y 3 9 6 36 81
Find f(7) for both functions

6. example
Identify the independent variable and the dependent variable for the table.
Let the independent variable be x and the dependent variable be f(x). Write a function for the table.
Price
Tax
$5.00
$.25
$3.00
$.15
$2.00
$.10
$.60
$.03

7. Using words to write a rule
In a Computer Museum, the exhibit is about 20 times larger than a normal-sized desktop computer. Write a function rule to describe the relationship.

8. example
Suppose you borrow money from a relative to buy a lawn mower that costs $245. You charge $18 to mow an average-size yard. Write a rule to describe your profit as a function of the number of lawns mowed.
Find f(9)

9. homeWork
Pg 81 # 1-12