Read the slope and y-intercept from y = mx + b

Answer Key - Grade 8 Math Worksheet

Circle the best answer, or write your answer on the line.

1. 1.

   In math club, Bo meets the line y = -2x − 7. What is its slope?

   -2
2. 2.

   In math club, Jun meets the line y = -x + 9. What is its slope?

   -1
3. 3.

   In math club, Milo meets the line y = -3x + 12. What is its y-intercept?

   12
4. 4.

   Noah graphs y = 4x + 6. At what point does the line cross the y-axis? Write it as (x, y).

   (0, 6)
5. 5.

   Pia graphs y = -2x − 3. At what point does the line cross the y-axis? Write it as (x, y).

   (0, -3)
6. 6.

   Ren graphs y = x − 7. At what point does the line cross the y-axis? Write it as (x, y).

   (0, -7)
7. 7.

   Zee sketches the line for y = 3x − 4. Which description matches its graph?

   • Crosses the y-axis at -4 and goes up 3 for each 1 across
   • Crosses the y-axis at 3 and goes down 4 for each 1 across
   • Crosses the y-axis at 4 and goes up 3 for each 1 across
8. 8.

   Bo graphs y = 2x and then y = 2x + 4. How does the new line compare with the first one?

   • Steeper, through the same point on the y-axis
   • Same steepness, moved up 4
   • Same steepness, moved down 4
   • Same steepness, moved 4 to the right
9. 9.

   Esme graphs y = -3x and then y = -3x − 5. How does the new line compare with the first one?

   • Steeper, through the same point on the y-axis
   • Same steepness, moved down 5
   • Same steepness, moved 5 to the left
   • Same steepness, moved up 5
10. 10.

    Luz's bath drains following L = 40 − 8m, with L the liters left after m minutes. What does the -8 in the rule tell you?

    • The bath starts with 8 liters
    • The bath gains 8 liters each minute
    • The bath takes 8 minutes to drain
    • The bath loses 8 liters each minute