Grade 9 · Math · Algebra 1

9th grade Is it a function? Vertical line test, and reading values from graphs and tables worksheet

6 printable versionsBuilding Confidence10 questions · answer keyFree · no account

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Is it a function? Vertical line test, and reading values from graphs and tables

Grade 9 Math Worksheet - Building Confidence

NameDate

Circle the best answer, or write your answer on the line.

1.
Jun plots dots from a bus-stop survey (one dot is a very sleepy stop). The vertical line at x = 3 touches the dots (3, 2) and (3, 6). Is it a function?
- Yes: every input has an output
- No: inputs 1 and 3 share the output 2
- No: the input 3 has two outputs, 2 and 6
2.
Kira plots bus numbers and ride times as dots. No vertical line touches two dots. Is it a function?
- No: the dots do not make a straight line
- Yes: no vertical line touches two dots
- No: inputs 2 and 4 share the output 5
3.
Luz plots game levels and star counts as dots. The vertical line at x = 2 touches the dots (2, 1) and (2, 4). Is it a function?
- Yes: every input has an output
- No: the dots do not make a straight line
- No: the input 2 has two outputs, 1 and 4
Noah's sunflower grows. The graph shows f(w), its height in cm after w weeks. What is f(2)?
Pia's toy rocket climbs. The graph shows f(s), its height in meters after s seconds. What is f(3)?
Ren fills a pool. The graph shows f(m), the liters in it after m minutes. What is f(1)?
Tala bikes a hilly road. The graph shows f(h), the km ridden after h hours. What is f(4)?
Read this first
Use the table
input x output f(x)
3 19
4 25
5 box
6 37
Ari fills a table for the robot rule f(x) = 6x + 1. What number goes in the box for input 5?
Bo fills a table for the lamp rule f(x) = 3x + 5. What number goes in the box for input 7?
Esme fills a table for the gift rule f(x) = 5x + 2. What number goes in the box for input 4?

input x	output f(x)
3	19
4	25
5	box
6	37

9th grade Is it a function? Vertical line test, and reading values from graphs and tables worksheet – printable — Print: 1 2 3 4 5 6

About this worksheet

Is it a function? Reading values from graphs and tables. Every version has 10 questions, and the answer key prints on the second page.

What your child will learn

I can tell from a graph or an equation whether each input has only one output.
I can read f(2) from a graph, and find the input for a given output.
I can finish a table from a rule and add values from a table and a rule.

Standard: F-IF.A.1, F-IF.A.2

Words to know

vertical line test: Slide a vertical line across the graph; two touches on one line mean not a function.

relation: Any rule or list that pairs inputs with outputs.

function: A relation where each input has exactly one output.

f(x) = c: The inputs whose output is c.

Common mistakes

Your child checked only that each input has an output and missed two dots on one up-and-down line.

Your child thought two inputs with the same output break a function.

Your child thought a function must be a straight line.

What to say

Ask: does any vertical line touch the graph twice?

Ask: does any one input have two different outputs?

Ask: must every function be straight, or only give one output for each input?

Questions parents ask

What is the most common mistake with is it a function? vertical line test, and reading values from graphs and tables?

Your child checked only that each input has an output and missed two dots on one up-and-down line.

How can I help my child with is it a function? vertical line test, and reading values from graphs and tables?

Ask: does any vertical line touch the graph twice?

Are these 9th grade math worksheets free to print?

Yes. All 6 printable versions at each level are free to print, with the answer key, and no account is needed.

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