Is there supposed to be a picture or a multi choice answer because there is none.Sorry
It went from 10 to -2, so you need to find the difference. The way you'd do this is: 10 - (-2). Do you know how to subtract a negative number from a positive number?
Answer: 3
You can find slope by using the 'rise over run' method. Find 2 clear points and count the number of units between those points, across the x axis and up the y axis. You should have 3/1 (y/x) as your slope.
The answer is B.55.8. Hope this helps!!