starting from the x coordinates, -8 and -3, subtract them and get 5. Moving on to the y coordinates, -2 and 1, you add 2 and 1 to get 3. In total after adding 5 and 3 you get 8. When the coordinates (that are in the same spot) are the same, you are subtract. But when they are different, you add. Sorry if this is confusing! But in the end, 8 is he answer.
