Answer:
-1/5
Step-by-step explanation:
Given the point A (9, 9) and B(7, -1)
The slope of the line AB is expressed as:
slope = Δy/Δx
slope = y2-y1/x2-x1
slope = -1-9/7-9
slope = -10/-2
slope = 5
For two lines to be perpendicular, the product of their slope must be -1
mM = -1
M is the slope of the line perpendicular to AB
Substitute m = 5 into the equation
5M = -1
M = -1/5
Hence the slope of a line that is perpendicular to the line joining point A and B is -1/5
