Testinar Grade 8 math

Reading Function Values

Learn to reason about and solve Grade 8 problems involving Reading Function Values.

CH04-02 Functions and Linear Relationships
Name
Date
Score
____ / 8
Directions Solve each problem. Show your reasoning on the page or on separate paper. Check the answer key only after finishing.

  1. The table below shows values of function \(f\). What is \(f(2)\)?

    Reading Function Values visual for G8-C04-T02-Q004
    1. \(7\)
    2. \(9\)
    3. \(11\)
    4. \(5\)

  2. The graph shows function \(g\). What is \(g(2)\)?

    Reading Function Values visual for G8-C04-T02-Q006
    1. \(2\)
    2. \(3\)
    3. \(1\)
    4. \(4\)

  3. A phone plan charges based on minutes used. The table shows the cost \(C(m)\) for \(m\) minutes. What is \(C(200)\)?

    Reading Function Values visual for G8-C04-T02-Q008
    1. \($20\)
    2. \($40\)
    3. \($30\)
    4. \($50\)

  4. The table shows \(f(x)\). If \(f(x)=8\), what is \(x\)?

    Reading Function Values visual for G8-C04-T02-Q009
    1. \(1\)
    2. \(2\)
    3. \(3\)
    4. \(4\)

  5. The graph shows function \(h\). Which of the following is true?

    Reading Function Values visual for G8-C04-T02-Q011
    1. \(h(2)=3\)
    2. \(h(1)=1\)
    3. \(h(3)=2\)
    4. \(h(4)=3\)

  6. The table shows values of \(f(x)=3x-2\). What is \(f(5)\)?

    Reading Function Values visual for G8-C04-T02-Q013
    1. \(13\)
    2. \(15\)
    3. \(12\)
    4. \(17\)

  7. The mapping diagram shows function \(f\). What is \(f(2)\)?

    Reading Function Values visual for G8-C04-T02-Q016
    1. \(5\)
    2. \(7\)
    3. \(9\)
    4. \(2\)

  8. From the graph of \(f(x)\), what is \(f(-1)\)?

    Reading Function Values visual for G8-C04-T02-Q020
    1. \(-1\)
    2. \(2\)
    3. \(1\)
    4. \(3\)
Teacher and parent reference

Answer key and explanations

  1. B. \(9\)

    Locate \(x=2\) in the table; the corresponding \(f(x)\) value is \(9\).

  2. B. \(3\)

    Locate \(x=2\) on the horizontal axis and read the corresponding \(y\)-coordinate from the graph: \(y=3\).

  3. C. \($30\)

    Locate \(m=200\) in the table; the cost is \($30\).

  4. C. \(3\)

    Find the output value \(8\) in the table; it corresponds to \(x=3\).

  5. B. \(h(1)=1\)

    From the graph, at \(x=1\) the point is at \((1,1)\), so \(h(1)=1\). Options A, C, and D are incorrect based on the plotted points.

  6. A. \(13\)

    Substitute \(x=5\): \(f(5)=3(5)-2=15-2=13\).

  7. B. \(7\)

    Follow the arrow from input \(2\) to output \(7\). Therefore, \(f(2)=7\).

  8. B. \(2\)

    Locate \(x=-1\) and read the corresponding \(y\)-value from the graph: \(y=2\). So \(f(-1)=2\).

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