Vocabulary
Evaluating Function Rules
Input and Outputs
Domain & Range
Is it a Function?
100
What is the definition of domain?
A set of input values (all values of x).
100
Evaluate f(2) if f(x)=-3x
f(2) = -6
100
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 meaning of the input(x) and the output (y).
Input (x) Variable: The number of minutes your friend spends studying. Output (y) Variable: The number of minutes you spend studying.
100
State the domain and range:
| x | y |
| 3 | 7 |
| 5 | 9 |
| 3 | 8 |
D: {3, 5} R: {7, 8, 9}
100
Is it a function? Justify your answer.
{(2, 3), (4, 5), ( -2, 6)}
Yes, each input has exactly one output.
200
What is the definition of range?
The set of output values (all values of y).
200
Evaluate f(7) if f(x)= -(4x+2)
f(7) = -30
200
Identify the Input (x) variable: The relationship between the number of hours worked and the amount of money earned.
The number of hours worked.
200
What is the domain and range of this function:
| x | y |
| 3 | 7 |
| 5 | 7 |
| 4 | 7 |
Domain: {3,4,5} Range: {7}
200
Using the vertical line test, does the graph of the points (1,3) and (1,5) represent a function?
No.
300
What is the definition of a function?
A relationship between input and output values. Each input has exactly one output value.
300
Evaluate f(-6) if f(x)=x^2 - 9
f(-6) = 27
300
Identify the output (y) variable: The relationship between your allowance and the number of chores you do.
Your allowance.
300
Do you look at the domain or the range to tell if a relation is a function?
You look at the domain.
300
Is it a function? Justify your answer.
| x | y |
| 2 | 4 |
| 1 | 5 |
| 2 | 6 |
No, the input of 2 has two different outputs.
400
Which variable is the input, and which one is the output?
(Which one is the x-variable, which one is the y-variable?)
x-variable is the input, y-variable is the output
(x - independent, y - dependent)
400
Evaluate f(x)=9 if f(x)=25 - 4x
x = 4
400
Identify the Input (x) and output variables (y): You are buying boxes of cookies at a bakery. Each box of cookies costs $4.
Input Variable: The number boxes of cookies purchased. Output Variable: How much you spend at the bakery.
400
If you were solving f(x) = -4 would -4 be part of the domain or range?
-4 would be part of the range
400
Is it a function? Justify your answer.
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Yes, it passes the Vertical Line Test.
500
What is the test to tell if a graph is a function?
Vertical Line Test
500
Evaluate f(x)=42 if f(x)=3x+15
x = 9
500
Identify the input (x) and output (y) variables: On your math quiz, you earn 5 points for each question that you answer correctly.
Input Variable: Number of questions answered correctly. Output Variable: Score on the quiz.
500
What would the range be for the function f(x) = 9
9
500
Is it a function? Justify your answer.
Yes, each input has exactly one output.