The slope of a straight line is commonly represented using the equation *y = mx + b* where *m* is the slope of the line. There is more on this here. This equation can be derived using any two points that lie on the line.

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The slope formula lets us calculate the value, *m*, using any two such points.

As shown below, the slope, m is calculated by dividing the difference in the y-values by the difference in the x-values. This is often referred to as being *the rise divided by the run*.

Slope = |
Y _{2} - Y_{1} |

X _{2} - X_{1} |

The formula states that the slope of a line is equal to the difference in y-values divided by the difference in x-values of two points on that line. This is also referred to as the rise divided by the run.

Slope (m) = |
Y _{2} - Y_{1} |

X _{2} - X_{1} |

m = |
11 - 5 |

10 - 3 _{} |

m = |
6 |

7 _{} |

Slope = 0.857

Rounded to nearest thousandth

It does not matter which points on the line you take as being (X_{1}, Y_{1}) and which is (X_{2}, Y_{2}) as the example below using the same two points as Example #1.

Slope (m) = |
Y _{2} - Y_{1} |

X _{2} - X_{1} |

m = |
5 - 11 |

3 - 10 _{} |

m = |
-6 |

-7 _{} |

Slope = 0.857

Rounded to nearest thousandth

Slope (m) = |
Y _{2} - Y_{1} |

X _{2} - X_{1} |

m = |
8 - (-8) |

6 - (-2) _{} |

m = |
16 |

8 _{} |

Slope = 2

Slope (m) = |
Y _{2} - Y_{1} |

X _{2} - X_{1} |

m = |
3 - (-4) |

-9 - 5 _{} |

m = |
7 |

-14 _{} |

Slope = -0.5

Use the worksheet(s) below for practice.

- Calculating the Slope of a Line - using m = (Y
_{2}- Y_{1})/(X_{2}- X_{1}) (2-Pages)

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