The slope is -4/7
You can visually count how many lines you go up and over from one to the other.
But another way to figure this out is the slope formula :
y2-y1 / x2-x1
The points as seen in the graph are (-4,3) and (3,-1)
Plus those values into the formula.
-1 - 3 / 3 - (-4)
-4/7