You and a friend are studying for a quiz. You want to get a higher score than your friend, so you decide to spend exactly 20 more minutes studying than your friend does. The relationship between these two variables can be expressed by the equation y=x+20, where x is the number of minutes your friend spends studying, and y is the number of minutes you spend studying. Identify the independent (x) and dependent (y) variables.
Independent (x) Variable: The number of minutes your friend spends studying. Dependent (y) Variable: The number of minutes you spend studying.
Write the table as ordered pairs (must be correct order)
x | y |
3 | 7 |
5 | 9 |
3 | 8 |
(3, 7) (3, 8 ) (5, 9)
What is the question asking you to find:
f(3) = 2x + 4
If you plug in 3 for x, what will y be?
Identify the independent (x) variable: The relationship between the number of hours worked and the amount of money earned.
The number of hours worked.
Write the graph as a table
x y
1 3
2 1
3 -1
4 2
5 0
6 6
Using the vertical line test, does the graph of the points (1,3) and (1,5) represent a function?
No, the line will be vertical and it will hit more than 1 time.
Identify the dependent (y) variable: The relationship between your allowance and the number of chores you do.
Your allowance.
Create a mapping for the graph ( use 5 input values)
See board for answer
Is it a function? Justify your answer.
x | y |
2 | 4 |
1 | 5 |
2 | 6 |
No, the input of 2 has two different outputs.
x-variable is the input
Identify the independent (x) and dependent variables (y): You are buying boxes of cookies at a bakery. Each box of cookies costs $4.
Independent Variable: The number boxes of cookies purchased. Dependent Variable: How much you spend at the bakery.
Create a graph to show the following:
(2, 3) (4, -1) (5,6) (0,2)
See board for answer
How can you tell when a mapping is a function? (Explain or show an example)
Each input should have only 1 arrow coming out of it!
What are the 5 representations for a function?
Graph, ordered pairs, table, mapping, equation
Evaluate f(x)=42 if f(x)=3x+15
x = 9
Identify the independent (x) and dependent (y) variables: On your math quiz, you earn 5 points for each question that you answer correctly.
Independent Variable: Number of questions answered correctly. Dependent Variable: Score on the quiz.
Create a mapping for the following:
(2, 3) (2, 4) (4, 2) (0, -1) (2, -1) (2, 3)
See board for answer.
Is it a function? Justify your answer.
Yes, each input has exactly one output.