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Calculate Slope With a Formula

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y= 1/2x +2

y= 1/2x +2

Jennifer Ledwith

Measure slope,  -m,  with the following formula:

            m= y21                    x2x1

Be careful:  x and y are not raised to the 2nd power.

Calculate the slope of y= 1/2x +2 using the following points on the graph:  (2,3) and   (-8,-2).

Follow these steps:

1. Label x1, y1,x2, y2:

x1,y1      x2,y2
(2,3)     (-8,-2)

2. Plug the numbers into the formula:

 m= -2−3
       -8−2

3. Simplify: 

m= -5
     -10

m= 1
      2

Slope is 1/2.

Notice that the slope is the same here as it was when we used points A and B on the graph. (See the article, How to Find the Slope of a Line With a Graph.)

For any given linear function, the slope is the same throughout the entire line.

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