State whether the slope of a line passing through (8, 8) and (6, -12) is positive, negative, zero or undefined

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.