To find the slope you could use the rise/run method.
To do this you would select any 2 points that's on the graph.....Such as (2, 3) & (6, 4)
Then from the point (2,3), count up (rise) Then over (run) until you get to the other point (6, 4)
Which in this case is 1/4 (rise/run) which is the slope of the graph.
Hope this helps! :)