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Grade 8 Introduction to Functions Worksheet with Answers

Grade 8 (US) · Year 9 (UK) · Class 8 (India) · Math

Unit 3: Functions & SlopeFunctionsCCSS 8.F.A.1

Deciding whether a relation is a function and evaluating functions written in f(x) notation. This free middle school worksheet has 12 questions and a full answer key. Print it or save it as a PDF — every answer is checked by code, not guessed.

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Introduction to Functions

Grade 8 · Math

Score___ / 12

Name

Class

Date

Learning goal: Functions · CCSS 8.F.A.1

Directions: Use the pictures to help you. Solve each problem. Show your work, then write your answer in the box.

Example

f(x) = 2x - 8. Find f(2).

Answer: -4

RememberFunctions

input xrulef(x) = 2x + 1outputx = 3 → 7x = 5 → 11
  1. 1

    f(x) = 2x. Find f(0).

    x = 0rulef(x) = 2x?
    Answer
  2. 2

    f(x) = -4x + 5. Find f(4).

    x = 4rulef(x) = -4x + 5?
    Answer
  3. 3

    f(x) = x^2 + 1. Find f(-1).

    x = -1rulef(x) = x^2 + 1?
    Answer
  4. 4

    f(x) = 3x + 1. Find f(6).

    x = 6rulef(x) = 3x + 1?
    Answer
  5. 5

    f(x) = 6x - 5. Find f(-5).

    x = -5rulef(x) = 6x - 5?
    Answer
  6. 6

    f(x) = -5x - 1. Find f(1).

    x = 1rulef(x) = -5x - 1?
    Answer
  7. 7

    f(x) = x^2 + 3. Find f(-1).

    x = -1rulef(x) = x^2 + 3?
    Answer
  8. 8

    f(x) = x^2. Find f(-2).

    x = -2rulef(x) = x^2?
    Answer
  9. 9

    Is {(-2, -1), (0, 6), (5, 0)} a function?

    -205-160input xoutput y
    YesNo
  10. 10

    f(x) = 4x + 8. Find f(-1).

    x = -1rulef(x) = 4x + 8?
    Answer
  11. 11

    f(x) = x^2 + 2. Find f(-3).

    x = -3rulef(x) = x^2 + 2?
    Answer
  12. 12

    f(x) = x^2 + 8. Find f(6).

    x = 6rulef(x) = x^2 + 8?
    Answer

★ Challenge corner for fast finishers

What is the units (ones) digit of 2^25?

How did I do?

Teacher's comments

Free printable worksheets with answer keys · aethelsystems.com/worksheets/math/8/functions_intro

Answer key (click to show)
  1. 1.0
  2. 2.-11
  3. 3.2
  4. 4.19
  5. 5.-35
  6. 6.-6
  7. 7.4
  8. 8.4
  9. 9.yes
  10. 10.4
  11. 11.11
  12. 12.44
  13. ★2 (challenge corner)

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Guides for teaching Introduction to Functions

What Are the Common Core and NGSS Standards? A Parent's GuideWhat learning standards are, how to read a code like 3.NF.A.1 or MS-PS1-2, what each grade covers in Math, English and Science, and how to use them at home.

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