Slope is rise/run, you can say that rise is the y values because y changes the height, and x is the run because changing the value makes it to left and right. You would just subtract y2 - y1 / x2 - x1. In this case, x1 and y1 represent the first point and x2 and y2 represent the second point. You would end up with -4 - 1 / 0 - (-10), which can be simplified to -1/2.
