If you mean points of (1, 5) and (-1, -1) then the slope works out as 3
Points: (1, -3) and (2, -5) Slope: -2
Points: (-2, 3) and (1, 1) Slope: -2/3
Points: (-1, -1) and (3, 15) Slope: 4
Points: (-1, -1) and (-3, 2) Slope: -3/2
The equation to figure out a slope is y1 - y2 / x1 - x2. In (1,9) and (-3,16), 9 is y1 and 16 is y2. 1 is x1 and -3 is x2. Now you have -7/4, which is your slope!
A slope of -3 is steeper.
If you mean points of (1, 5) and (-1, -1) then the slope works out as 3
The slope of two lines are perpendicular only if their slopes multiplied together equal -1 (m1*m2 = -1). So if a line has a slope of -3 then a line perpendicular to this one has a slope of -1/-3 or 1/3.
Points: (1, -3) and (2, -5) Slope: -2
Points: (-2, 3) and (1, 1) Slope: -2/3
Points: (-2, 3) and (1, 1) Slope: -2/3
Points: (-3, -1) and (3, -2) Slope: -1/6
Points: (1, 3) and (3, -2) Slope: -5/2 or -2.5
Points: (1, 7) and (-3, 2) Slope: 5/4 or 1.25
If the points are: (4, 3) and (6, 1) then the slope works out as -1
Points: (-1, 2) and (3, 3) Slope: 2-3/-1-3 = 1/4