In order to find the slope, m, you would have to find the change in y over the change in x.
y2 - y1 -12 - 8 -20 -10
---------- = ---------- = ------- = -------- = 5
x2 - x1 6 - 8 -2 -2
The negatives would cancel out and you would get 5 as your slope, which is positive.