I can help with 17-20:)
Slope = m = y2 - y1/ x2 -x1
So, you have already found the y1 and y2 and x1 and x2.
So, plug the numbers into the equation:
3 - 1/(-5) - (-2)
4 - (-3)/(-1) - 1
(-5) - 5/2 - 4
2 - (-1)/(-1) - 1
Then solve.
(Btw, the formula looks like this:
Hope this helps!!!