SOLUTION: What's the slope of the line that goes through these pair of points: (6,8) and (8,9) ?

Plot the two points:



Draw a straight line through them:



The line goes uphill to the right, so its slope
will be a positive number.

Draw a green line from (6,8) till it is exactly below (8,9).



That green line is called a "run". Notice that it is 2 units
long,  So the run is 2

Next draw a red line from the end of the green line up to the
point (8,9).



That red line is called a "rise". Notice that it is 1 unit
long,  So the rise is 1.

Now the slope is defined as 

So the slope is 1/2, positive because it goes uphill to
the right.  Lines that go downhill to the right have
slopes which are negative.

Edwin