Hi there! Your answer is -1/9
Please see an explanation for a better and clear understanding to your problem.
Any questions about my answer and explanation can be asked through comments!:)
Step-by-step explanation:

The formula above is slope formula. We will be using this to find a slope of a line.
From the graph, there are two points which are (4,0) and (-5,1).
You can either let (4,0) = (x1, y1) or (x2, y2) but I will be letting (-5,1) =(x2, y2)
Substitute the coordinate points in.

Hence, the slope is - 1/9. If you are curious where m-term comes from, it comes from y = mx+b where m = slope and b = y-intercept.