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 - Building Confidence

NameDate

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

In math club, Ari fills a table for y = 3x + 5: 0 | 5; 1 | 8; 2 | 11. What is the y-intercept of the line?
In math club, Bo fills a table for y = 2x + 7: 0 | 7; 1 | 9; 2 | 11. What is the slope of the line?
In math club, Esme fills a table for y = 4x − 1: 0 | -1; 1 | 3; 2 | 7. What is the y-intercept of the line?
Kira copies the rule y = x + 6 from the board. What is the slope of its line?
Luz copies the rule y = -4x + 3 from the board. What is the slope of its line?
Milo copies the rule y = x − 8 from the board. What is the slope of its line?
Noah copies the rule y = 6x − 2 from the board. What is the y-intercept of its line?
Pia copies the rule y = 7x + 4 from the board. What is the y-intercept of its line?
9.
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 up 4 for each 1 across
- Crosses the y-axis at 4 and goes down 3 for each 1 across
10.
Ari sketches the line for y = x + 3. Which description matches its graph?
- Crosses the y-axis at 3 and goes up 1 for each 1 across
- Crosses the y-axis at 1 and goes up 3 for each 1 across
- Crosses the y-axis at 3 and stays flat

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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