Your slope will be 0 because you will take one y value minus the other and get 2 --> 10-8=2. Then you will take the x-values in and subtract them in the same orders as the y-values and get 0 --> 5-5=0. Slope is rise (y) over run (x) so your slope would usually be your y/x but your slope can not be 2/0 because 2 parts of nothing is nothing so your slope will end up being 0.