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.

   Esme meets the rule y = 6(x + 7) in math club. What is the y-intercept of its line?

   42
2. 2.

   Jun meets the rule y = 4(x − 3) in math club. What is the y-intercept of its line?

   -12
3. 3.

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

   4
4. 4.

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

   -4
5. 5.

   Zee meets the line y = 2.5x − 0.5 in math club. What is its y-intercept?

   -0.5
6. 6.

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

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

   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 gets 1.5 cm taller each hour
   • The candle gets 1.5 cm shorter each hour
   • The candle starts 1.5 cm tall
   • The candle burns out after 1.5 hours
8. 8.

   After sunset, the temperature at Pia's campsite follows T = -2h + 6, with T in °C after h hours. What does the 6 tell?

   • It was 6 °C at sunset (hour 0)
   • It will be 6 °C in 2 hours
   • The temperature drops 6 °C each hour
9. 9.

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

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

    Kira meets the line y = 5x ÷ 3 + 2 in math club. What is its slope?

    5/3