Work Shown:
Slope = rise/run
Slope = (change in y)/(change in x)
Slope = (2-p)/(-10-(-6))
Slope = (2-p)/(-10+6)
Slope = (2-p)/(-4)
Set this equal to the stated slope -1/6 and solve for p
(2-p)/(-4) = -1/6
6(2-p) = -4(-1)
12-6p = 4
-6p = 4-12
-6p = -8
p = -8/(-6)
p = 4/3