Graphing Linear Functions Quiz

Grade 9 · Math · Quiz

Test your skills with slope, y-intercept, graphing, and interpreting linear functions.

Questions

1. What is the slope of the line passing through (0, 3) and (4, 11)?

   1. 2
   2. 3
   3. 4
   4. 8
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   Answer: 2

   m = (11 − 3)/(4 − 0) = 8/4 = 2.

2. A horizontal line has an undefined slope.

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   Answer: False

   A horizontal line has a slope of 0; it is the vertical line that has undefined slope.

3. What is the y-intercept of y = 4x − 7?

   1. (0, 4)
   2. (0, −7)
   3. (7, 0)
   4. (−7, 0)
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   Answer: (0, −7)

   The y-intercept is b = −7; the point is (0, −7).

4. The slope of a vertical line is ___.

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   Answer: undefined

   A vertical line has the same x for all y, so run = 0 and division by zero is undefined.

5. Which line is perpendicular to y = 3x + 2?

   1. y = 3x − 1
   2. y = −1/3 x + 5
   3. y = 1/3 x + 2
   4. y = −3x + 2
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   Answer: y = −1/3 x + 5

   Perpendicular slope = negative reciprocal of 3 = −1/3.

6. The point (2, 5) lies on the line y = 2x + 1.

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   Answer: True

   y = 2(2) + 1 = 5 ✓.

7. Convert to slope-intercept form: 2x + y = 10

   1. y = 2x + 10
   2. y = −2x + 10
   3. y = 2x − 10
   4. y = 10 − x
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   Answer: y = −2x + 10

   Subtract 2x from both sides: y = −2x + 10.

8. The x-intercept of y = 2x − 6 is (___,0).

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   Answer: 3

   Set y = 0: 0 = 2x − 6 → x = 3.

9. Which equation has a slope of zero?

   1. x = 4
   2. y = 4
   3. y = 4x
   4. y = x + 4
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   Answer: y = 4

   y = 4 is a horizontal line — constant output means slope = 0.

10. Find the slope between (−2, 1) and (4, 13).

    1. 1
    2. 2
    3. 3
    4. 6
    Show answer

    Answer: 2

    m = (13 − 1)/(4 − (−2)) = 12/6 = 2.

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