Slope Formula and How to Use It

Slope (m) is defined as rise divided by run. The rise is defined as the change in the y value between two coordinates. The run is defined as the change in the x value between two coordinates. This equation can also be thought of as the equation for Tangent (). When talking about slope the opposite is now the rise, the adjacent is now the run, and the hypotenuse is now the steepness of the line. *Tip: Always use nice points (not decimal points) when trying to find slope because it makes it easier.*

Types of Slopes

Positive Slope: is positive in the equation (x + 3) and on a graph it goes up from left to right. The blue line in the picture.

Negative Slope: has at least one negative number in the equation (x + 1) and goes down from left to right. The red line in the picture. 

Horizontal Lines: the rise in the slope is 0. The purple line in the picture

Undefined (vertical lines): because the run is 0 and the denominator of a fraction can’t be zero it’s marked as undefined and does not appear in the picture.

Slope Formula

The slope formula is used to find the slope when you don’t have a graph or the numbers are too big to figure it out in your head.

Slope = =
The y1 and x1 is from the first point and y2 and x2 is from the second point.

Ex: (1,3), (3,9) find the slope