Grade 8 · Math

8th grade Read the slope and y-intercept from y = mx + b worksheet

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

Grade 8 Math Worksheet - Challenge Me

NameDate

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

Jun meets the rule y = 4(x − 3) in math club. What is the y-intercept of its line?
Kira meets the rule 2y = 8x + 6 in math club. What is the slope of its line?
Luz meets the rule 3y = 6x − 12 in math club. What is the y-intercept of its line?
Ren meets the line y = 3x ÷ 4 − 6 in math club. What is its slope?
Tala meets the line y = -2x ÷ 5 + 1 in math club. What is its slope?
Ari meets the line y = -x ÷ 2 − 9 in math club. What is its y-intercept?
7.
Bo graphs y = 2x + 1 and then y = 2x + 6. How does the new line compare with the first one?
- Same steepness, moved up 6
- Same steepness, moved down 5
- Steeper, through the same point on the y-axis
- Same steepness, moved up 5
8.
Jun graphs y = 4x − 2 and then y = 4x + 5. How does the new line compare with the first one?
- Same steepness, moved up 7
- Steeper, through the same point on the y-axis
- Same steepness, moved up 5
- Same steepness, moved down 7
9.
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 will be 6 °C in 2 hours
- It was 6 °C at sunset (hour 0)
- The temperature drops 6 °C each hour
Luz meets the line y = 0.25x − 3.5 in math club. What is its y-intercept?

Read the slope and y-intercept from y = mx + b. Every version has 10 questions, and the answer key prints on the second page.

I can read the slope m and the y-intercept b from y = mx + b, keeping their signs, and write where the line crosses the y-axis as (0, b).
I can first rewrite a rule such as y = 5 + 3x, y = 6(x + 7), 2y = 8x + 6 or y − 4 = 2x as y = mx + b.

Standard: 8.EE.B.6 (y = mx + b part), 8.F.A.3

slope (m): The number multiplying x: how much y changes for each 1 of x.

y-intercept (b): The number alone: the output when x = 0, where the line crosses the y-axis.

slope-intercept form: A rule written y = mx + b, with y alone on one side.

y-axis: The up-and-down axis, where x = 0.

slide (translate): Move a line up or down without turning it.

Your child mixed up the slope and the y-intercept. In y = 3x + 5, ask: which number goes with x (the change for each step), and which is the start?

Your child read the right number but left off its minus sign.

Your child thought a rule like y = x + 6 has slope 0 because no number is written in front of x.

Ask: is the number added or taken away in the rule?

Ask: what is 1 times x?

What is the most common mistake with read the slope and y-intercept from y = mx + b?

Your child mixed up the slope and the y-intercept. In y = 3x + 5, ask: which number goes with x (the change for each step), and which is the start?

Are these 8th grade math worksheets free to print?

Yes. All 6 printable versions at each level are free to print, with the answer key, and no account is needed.

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