In order to find the slope, you should remember the formula (Y1-Y2)/(X1-X2) the order of the x and ys do not really matter, but the they should be the same for the top and bottom. In this situation, you can do (4-6) which represent your Y1 and Y2 and then divide by (1 minus -1) which are your xs, this simplifies to -2/2 or simply, a slope of -1
