Pause and Reflect

If you select a different pair of numbers from the table, do you get a different value for the slope? Why do you think that is the case?

Check Your Answer

No. Linear functions have a constant slope, or constant rate of change, so it will not matter which pair of corresponding values that you select from the table, you will always get the same slope.

How is this method related to the slope formula?

Check Your Answer

The slope formula, m = y₂ – y₁ x₂ – x₁ , also uses the ratio of the change in y to the change in x. If you select two points from the table, you can also use the slope formula to determine the slope of the line represented by the ordered pairs in the table.

Practice

Using the tables below, find the change in y and x to determine the slope.

1. X	Y
   2	3
   5	9
   6	11
   8	15
   10	19

   
   Interactive popup. Assistance may be required.

   Check Your Answer

   The slope is 2. slope = six over three 6 3 = 2.
   

2. X	Y
   4	-10
   5	-13
   6	-16
   7	-19
   8	-22

   
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   Check Your Answer

   The slope is -3. slope = negative three over one -3 1 = -3.
   

3. X	0	3	6	9
   Y	5	7	9	11

   
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   Check Your Answer

   Slope = two over three 2 3 .