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Finding the slope between two points

Slope is change in y over change in x, subtracted in the same order.

The common mistake

Putting x on top (run over rise) or subtracting in mismatched order, which flips the sign.

Instead: Use m = (y₂ − y₁) / (x₂ − x₁), taking both values from the same point first.

Worked example with Guide me

Find the slope through (1, 2) and (3, 6).

  1. Sugar · What's the change in y, second point minus first?
    Student · 6 − 2 = 4.
  2. Sugar · And the change in x, same order?
    Student · 3 − 1 = 2.
  3. Sugar · So the slope?
    Student · 4 ÷ 2 = 2.

Answer: m = 2

Try 3 practice questions

  1. 1. Slope through (0, 1) and (2, 7)?

    Show answer

    3

  2. 2. Slope through (−1, 4) and (3, −4)?

    Show answer

    −2

  3. 3. Slope through (2, 5) and (6, 5)?

    Show answer

    0 (horizontal line)

Quick answers

What is the most common mistake with finding the slope between two points?
Putting x on top (run over rise) or subtracting in mismatched order, which flips the sign.
How do I get finding the slope between two points right?
Use m = (y₂ − y₁) / (x₂ − x₁), taking both values from the same point first.
Can you show a worked example?
Find the slope through (1, 2) and (3, 6). m = 2

Related concepts

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