Start from (19,8), take 2 minutes to travel 8 blocks back, end at (21,0).
Step-by-step explanation:
You calculate it by taking the change in y's over the change in x's. So (y1-y2)/(x1-x2). You get the equation (-5 - 3)/(5 - 7) which equals 4. 4 is the slope.
