Vocabulary
Independent & Dependent
Domain & Range
Is it a Function?
5
What is the definition of an independent variable?
A variable whose values affect the values of another variable (dependent variable). It is usually found on the x-axis of a graph.
5
Identify the independent and dependent variables: 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.
5
State the domain and range: 
D: -4 ≤ x < infinity
R: all real numbers (negative infinity < y < infinity)
5
B= {(0, 1), (-1, 2), (0, 3), (-2, 4), (-1, 5)}
Set B is not a function since ordered pairs (0, 1) and (0, 3) have the same first element.
10
What is the definition of domain?
A set of input values (all values of x).
10
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=f+20, where f is the number of minutes your friend spends studying, and y is the number of minutes you spend studying. Identify the independent and dependent variables.
Independent Variable: The number of minutes your friend spends studying.
Dependent Variable: The number of minutes you spend studying.
10
State the domain and range:
(2, 5) (6, -1) (-9, 0)
D: {-9, 2, 6}
R: {-1, 0, 5}
10
Is it a function? Justify your answer.
{(2, 3), (4, 5), ( -2, 6)}
Yes, each input has exactly one output.
10
What is the definition of range?
The set of output values (all values of y).
10
Identify the independent variable: The relationship between the number of hours worked and the amount of money earned.
The number of hours worked.
10
State the domain and range:
| x | y |
| 3 | 7 |
| 5 | 9 |
| 3 | 8 |
D: {3, 5}
R: {7, 8, 9}
10
Using the vertical line test, does the graph of the points (1,3) and (1,5) represent a function?
No, the points fail the Vertical Line Test.
10
What is the test to tell if a graph is a function?
Vertical Line Test
10
Identify the independent and dependent 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.
10
State the domain and range: 
D: x ≠−2
R: negative infinity < y ≤ 3
10
Is it a function? Justify your answer. 
Yes, each input has exactly one output.
15
What is the definition of a function?
A relationship between input and output values. Each input has exactly one output value.
15
Identify the dependent variable: The relationship between your allowance and the number of chores you do.
Your allowance.
15
State the domain and range:
D: {1, 2, 3, 4, 5, 6}
R: {-1, 0, 1, 2, 3, 6}
15
Is it a function? Justify your answer.
| x | y |
| 2 | 4 |
| 1 | 5 |
| 2 | 6 |
No, the input of 2 has two different outputs.