there are infinite possibilities
If you mean points of (4,-1) and (-1, 4) then the slope of the line works out as -1
Points: (-6, 4) and (3, -4) Slope: -8/9
Points: (6, -4) and (3, 4) Slope: -8/3
Points: (2, 6) and (-3, -4) Slope: 2
If you mean points of: (-1, 8) and (5, -4) then the slope is -2