To find the slope going from (1991,230) to (1997,350) we are going to calculate the change in y over the change in x, or the rise over the run. The change is the difference between the two coordinates. So if the y-coordinate of a point goes from 230 to 350, the change in these numbers is 120 (since  ). If the x-coordinate changes from 1991 to 1997, then the change is 6 (since  ). So to calculate the slope we use this formula:
Slope:
 where m is the slope
So now we let  , , , Now plug these numbers into the slope formula:
So after simplification the slope is  |
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