← Back to Topic 10

Identifying Functions: Classroom Packet

Grade 8 Algebra: Identifying Functions

Name: ______________________Date: ____________Score: ____ / 8

Level 1

Sets of ordered pairs

  1. 1. Is the relation a function:
    {(1,2),(2,4),(3,6)}\{(1, 2), (2, 4), (3, 6)\}
  2. 2. Is the relation a function:
    {(1,3),(1,5),(2,7)}\{(1, 3), (1, 5), (2, 7)\}
  3. 3. Is the relation a function:
    {(0,1),(1,1),(2,1)}\{(0, 1), (1, 1), (2, 1)\}
  4. 4. Is the relation a function:
    {(2,5),(3,5),(2,6)}\{(2, 5), (3, 5), (2, 6)\}
  5. 5. Is the relation a function:
    {(−1,4),(0,3),(1,2)}\{(-1, 4), (0, 3), (1, 2)\}
  6. 6. Is the relation a function:
    {(4,1),(5,2),(4,3)}\{(4, 1), (5, 2), (4, 3)\}
  7. 7. Is the relation a function:
    {(3,0),(−3,0),(6,1)}\{(3, 0), (-3, 0), (6, 1)\}
  8. 8. Is the relation a function:
    {(7,2),(8,3),(9,4)}\{(7, 2), (8, 3), (9, 4)\}

Answer Key

Level 1

  1. 1. Yes\text{Yes}
  2. 2. No (x=1 twice)\text{No}\ (x = 1 \text{ twice})
  3. 3. Yes\text{Yes}
  4. 4. No (x=2 twice)\text{No}\ (x = 2 \text{ twice})
  5. 5. Yes\text{Yes}
  6. 6. No (x=4 twice)\text{No}\ (x = 4 \text{ twice})
  7. 7. Yes\text{Yes}
  8. 8. Yes\text{Yes}

Grade 8 Algebra: Identifying Functions

Name: ______________________Date: ____________Score: ____ / 8

Level 2

Tables

  1. 1. Is the relation a function:
    x1234y57911\begin{array}{c|cccc} x & 1 & 2 & 3 & 4 \\ \hline y & 5 & 7 & 9 & 11 \end{array}
  2. 2. Is the relation a function:
    x1123y2468\begin{array}{c|cccc} x & 1 & 1 & 2 & 3 \\ \hline y & 2 & 4 & 6 & 8 \end{array}
  3. 3. Is the relation a function:
    x−2−101y4101\begin{array}{c|cccc} x & -2 & -1 & 0 & 1 \\ \hline y & 4 & 1 & 0 & 1 \end{array}
  4. 4. Is the relation a function:
    x0122y3456\begin{array}{c|cccc} x & 0 & 1 & 2 & 2 \\ \hline y & 3 & 4 & 5 & 6 \end{array}
  5. 5. Is the relation a function:
    x5555y1234\begin{array}{c|cccc} x & 5 & 5 & 5 & 5 \\ \hline y & 1 & 2 & 3 & 4 \end{array}
  6. 6. Is the relation a function:
    x1234y6666\begin{array}{c|cccc} x & 1 & 2 & 3 & 4 \\ \hline y & 6 & 6 & 6 & 6 \end{array}
  7. 7. Is the relation a function:
    x−1010y2345\begin{array}{c|cccc} x & -1 & 0 & 1 & 0 \\ \hline y & 2 & 3 & 4 & 5 \end{array}
  8. 8. Is the relation a function:
    x2468y1313\begin{array}{c|cccc} x & 2 & 4 & 6 & 8 \\ \hline y & 1 & 3 & 1 & 3 \end{array}

Answer Key

Level 2

  1. 1. Yes\text{Yes}
  2. 2. No\text{No}
  3. 3. Yes\text{Yes}
  4. 4. No\text{No}
  5. 5. No\text{No}
  6. 6. Yes\text{Yes}
  7. 7. No\text{No}
  8. 8. Yes\text{Yes}

Grade 8 Algebra: Identifying Functions

Name: ______________________Date: ____________Score: ____ / 8

Level 3

Equations

  1. 1. Does the equation make y{y} a function of x{x}:
    y=3x−2y = 3x - 2
  2. 2. Does the equation make y{y} a function of x{x}:
    x=4x = 4
  3. 3. Does the equation make y{y} a function of x{x}:
    y=x2y = x^2
  4. 4. Does the equation make y{y} a function of x{x}:
    x=y2x = y^2
  5. 5. Does the equation make y{y} a function of x{x}:
    y=5y = 5
  6. 6. Does the equation make y{y} a function of x{x}:
    x2+y2=25x^2 + y^2 = 25
  7. 7. Does the equation make y{y} a function of x{x}:
    y=∣x∣y = |x|
  8. 8. Does the equation make y{y} a function of x{x}:
    y=−2x+7y = -2x + 7

Answer Key

Level 3

  1. 1. Yes\text{Yes}
  2. 2. No\text{No}
  3. 3. Yes\text{Yes}
  4. 4. No (x=4⇒y=±2)\text{No}\ (x = 4 \Rightarrow y = \pm 2)
  5. 5. Yes\text{Yes}
  6. 6. No (x=0⇒y=±5)\text{No}\ (x = 0 \Rightarrow y = \pm 5)
  7. 7. Yes\text{Yes}
  8. 8. Yes\text{Yes}