Step-by-step explanation:
why ? you have started it correctly already, as I can see by the margins you made on the graph.
you analyzed the problem correctly, approached the solution correctly and gathered all necessary data.
so, I am not sure, what your problem is.
if you don't know what a slope is, then I don't understand why you did what you did so far.
the slope is expressed as the ratio
y coordinate change / x coordinate change
when going from one point to the other.
for these 2 points you marked, you also showed that
x changes by +2 (from 2 to 4).
y changes by +6 (from -4 to 2).
so, the slope is +6/+2 = 3.
that's it. that is all to it.