What is the slope of line a?

Answer:
-1/3
Step-by-step explanation:
Slope is defined as "rise over run". If you count out the units, you should be able to see that your rise is 1 and your run is 3 and is pointing downward, so your answer is -1/3.
Alternatively you could use Slope Formula: [tex]m = \frac{y2-y1}{x2-x1}[/tex]