Answer is -1/5
Step by step
Using the slope formula change in y over change in x
(y2-y1) over (x2-x1)
Using points (1,3) and (6,2)
(2-3) over (6-1)
(-1) over (5)
-1/5
You can also find slope on the graph
From point to point
You go down -1 and over +5
So -1/5
Problem solved