Grade 8 · Pre-Algebra

Grade 8 Pre-Algebra — Slope / y = mx + b questions and answers

The #1 Grade 8 math search in the US. Written in American English for students, parents, and teachers in the United States.

Practice quiz

Open a card to see the answer. These are original practice items for US elementary students — not a state test copy.

1. In y = mx + b, m is the

Answer: slope

Rise over run.

2. In y = mx + b, b is the

Answer: y-intercept

The line crosses the y-axis at (0, b).

3. Slope is calculated as

Answer: (y₂ − y₁) / (x₂ − x₁)

Vertical change over horizontal change.

4. A line with slope 0 is

Answer: horizontal

y does not change.

5. A vertical line has

Answer: undefined slope

You would divide by zero.

6. The slope of the line through (1, 2) and (3, 6) is

Answer: 2

(6 − 2) / (3 − 1) = 4/2 = 2.

7. y = −3x + 5 has a slope that is

Answer: negative, so the line falls left to right

Negative m means the line decreases.

8. Parallel lines have

Answer: the same slope

Perpendicular slopes are opposite reciprocals.