Determine the slope of the line that passes through the points.
1. (2,3), (4,5)
2. (1,6), (-4,-7)
3. (-6,1), (-2,1)
4. (-2,2), (-5,-2)
5. (4,-8), (-4,7)
6. (5,-3), (-1,2)
7. (-1,-3), (2,-3)
8. (-2,-5), (1,-3)
9. (2.2,3.1), (-2,5)
10. (2,3.2), (1.1,-5)
11. (-1,1.1), (-3,-2)
12. (1,-3), (4,-2)
13. (6,-3), (-2,5.2)
14. (5,-4), (-1,3)
15. (2.1,3.4), (4.1,-5)
16. (5,1), (3.2,-2)
17. (-2,-2), (0.3,2)
18. (-5,-1), (5.4,6)
19. (1,1), (7,8)
20. (4,3), (5,1)