To find the slope, we have to use the formula m = (y2-y1)/(x2-x1), where y2 is the y value in the second coordinate, x2 is thr x value of the second coordinate and etc. Plug in the coordinates and solve.
(10-7)/(-1-(-7)) = 3/(-1+7) = 3/6 = 1/2. The slope is 1/2, or 0.5.