Sewanhaka High School
Math 8
Per:________________
Name:________________________________
Mrs. Lidowsky, Principal
Mr. Long, Teacher
Date:_____________________
H.W. #32: Ditto
DO-NOW #32: Answer the following questions:
1) Let f(x) = 3x + 4. Find f(x) when x = 1.
2) Let g(x) = -2x + 6. Find x when g(x) = 14.
3)
4) Kaisha and Taisha bought
7
1
of a yard of fabric to make a class project. They only used of a yard. How much
8
3
fabric was left?
Topic: Functions
Main Idea: Graphing Functions
Aim:
RECALL
NOTES
(Based on Life Science fact):
After a person turns 30 years
old, that person shrinks .06
centimeter per year. (No! Mr.
Long does not shrink 6000 cm
per year. Only 600 cm per
year.) If a person shrinks .06
cm per year, how many
centimeters would they have
shrunk when that person turns
35, 42, and 57?
# of cm you
start
shrinking after
cut off
shrinking age
n = present
age
(Input)
How to find the # of
Start of
shrinking cm shrunk
after cut off
age
shrinking age.
# of cm shrunk at
present age: f(n)
(Ans. or Output)
(Rule:
)
NOTE: Some statements and definitions to go over.
1) n is used for the present age (your first number) and that is called your input.
(NOTE: You do not have to use n as your variable. You can use any letter. Try not to use f.)
2) The set of input values (35, 42, and 57) in a function is called the ________________.
3) The operation performed, .06(n – 30), is called your rule.
4) f(n) is called your output (second number or answer). This is read as the function of n or just f of n.
5) The set of output values (.3, .72, and 1.62) is the ________________.
6) A function table organizes the input, rule, and output.
(NOTE: You really do not need the first and 3rd columns of our previous table. All you need is 3 columns.)
Write the rule for the following function: The second number is three
less than the first number. What pairs of numbers am I thinking of.
Graph the previous function using a table of values.
Drill:
1) Write the rule for the following function: The second number is
one-third of the first number. What pairs of numbers am I thinking of.
Graph the
previous
function using a
table of values.
2) Stacy says that f(6) for f(n) = 2n2 – 18 is 54. Jen says that f(6) = 126 for the same rule. Who is correct and why?
Summary:
If time:
3) Copy and complete the following table. Graph f(x).
x
3x
f(x)
-2
0
2
4
6