Is the line through (0,2)and (-1,1)perpendicular to the line through (6,-1)and (9,-2

Question

I don't know how to find if they are perpendicular or parallel or neither

Answer 1

For a line with slope m, the perpendicular line has slope -1/m

 

(0,2), (-1,1)

m = (1-2)/(-1-0) = -1/–1 = 1

perpendicular line must have slope -1/1 = -1

 

(6,-1), (9,-2)

m = (-2-(-1))/(9-6) = -1/3

 

These lines are NOT perpendicular.

 

Note:  Parallel lines have the same slope.

These lines are neither perpendicular nor parallel.