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

Answer Key - Grade 8 Math Worksheet - Challenge Me

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

1. 1.

   Kira meets the rule 2y = 8x + 6 in math club. What is the slope of its line?

   4
2. 2.

   Luz meets the rule 3y = 6x − 12 in math club. What is the y-intercept of its line?

   -4
3. 3.

   Milo meets the rule y − 4 = 2x in math club. What is the y-intercept of its line?

   4
4. 4.

   Noah meets the rule y + 6 = 5x in math club. What is the y-intercept of its line?

   -6
5. 5.

   Ari meets the line y = -x ÷ 2 − 9 in math club. What is its y-intercept?

   -9
6. 6.

   Esme graphs y = -x + 3 and then y = -x − 4. How does the new line compare with the first one?

   • Steeper, through the same point on the y-axis
   • Same steepness, moved down 7
   • Same steepness, moved up 7
   • Same steepness, moved down 4
7. 7.

   Jun graphs y = 4x − 2 and then y = 4x + 5. How does the new line compare with the first one?

   • Same steepness, moved up 5
   • Same steepness, moved down 7
   • Steeper, through the same point on the y-axis
   • Same steepness, moved up 7
8. 8.

   Noah's candle follows h = 24 − 1.5t, with h its height in cm after t hours. What does the -1.5 in the rule tell?

   • The candle starts 1.5 cm tall
   • The candle burns out after 1.5 hours
   • The candle gets 1.5 cm taller each hour
   • The candle gets 1.5 cm shorter each hour
9. 9.

   In Ren's puzzle game, the stars follow s = 10n + 50 after n levels. What does the 10 tell?

   • There are 10 levels
   • Each level adds 10 stars
   • The game starts with 10 stars
10. 10.

    Luz meets the line y = 0.25x − 3.5 in math club. What is its y-intercept?

    -3.5