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Grade 8 Math — Introduction to graphs

Plot and read points on a grid, read a line graph, and work out values from a simple linear relation.

Name: ________________________

Before you start

This graph follows one journey from start to finish, with time along the bottom and distance up the side. Find out what each stretch of the line says about it.

1234
  1. 1. Rising — moving away
  2. 2. Flat — standing still
  3. 3. Steeper — faster
  4. 4. The origin

Flat does not mean time has stopped — the clock still runs along the bottom. It means the distance stopped changing, and standing still is exactly what that looks like on a graph.

  1. 1.A point sits 4 units to the right of the origin and 7 units up. Write its y-coordinate.

  2. 2.Sort each point by where it sits on the grid.

    Groups: On the x-axis · On the y-axis · On neither axis

    • (0, -1)
    • (-4, 0)
    • (6, 6)
    • (0, 5)
    • (3, 0)
    • (2, 7)

  3. 3.A car travels at a steady 50 miles per hour. On a distance-time graph, how far has it gone after 3 hours, in miles? Give just the number.

  4. 4.This distance-time graph shows one journey in three parts. Tap the part where the car was not moving.

    Write the number of the part.

    123

  5. 5.For the relation y = 2x + 1, what is y when x is 5?

  6. 6.On a distance-time graph, what does a flat horizontal part of the line mean?

    • a) The object is not moving
    • b) The object is going backwards
    • c) The graph has been drawn wrongly
    • d) The object is speeding up

  7. 7.For the relation y = 4x - 1, match each value of x to its value of y.

    • x = 1
    • x = 2
    • x = 3
    • x = 5
    • x = 6
    • 11
    • 19
    • 23
    • 7
    • 3

  8. 8.What is the x-coordinate of the point (5, 3)?

Answer key — Grade 8 Math — Introduction to graphs

  1. 1. 7
  2. 2. (3, 0) → On the x-axis; (0, 5) → On the y-axis; (2, 7) → On neither axis; (-4, 0) → On the x-axis; (0, -1) → On the y-axis; (6, 6) → On neither axis
  3. 3. 150
  4. 4. 2 — Stopped by the roadside
  5. 5. 11
  6. 6. a) The object is not moving
  7. 7. x = 1 → 3; x = 2 → 7; x = 3 → 11; x = 5 → 19; x = 6 → 23
  8. 8. 5