How do we determine the slope of a line given two points on the line?
Given two points,
we can determine the slope of a line by using the slope formula. Earlier, you found out that:
Further, you learned that the change in y is found from subtracting the y coordinates and that the change in x is found from subtracting the x coordinates. This leads us to the slope formula:
We will plug in two given points into the slope formula to determine the slope of the line.
Example
Given the following two points, determine the slope:
Note - I could have labeled my first point as (x2,y2) and my second point as (x1,y1) but I always like to start with (x1,y1). You should get the same answer for slope regardless of which point you labeled first.
Horizontal and Vertical Lines
Practice
Determine the slope given the following two points:
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