Question

Find the slope of the line perpendicular to AB where A( 5 , - 6) and B(2 , -7 )

• A. -2
• B. -3
• C. 1
• D. 2

Answer 1

The correct option is B -3

Slope of line joining two points $(x_1,y_1)$ and $(x_2,y_2)$ is $\frac{y_2-y_1}{x_2-x_1}$
So, Slope of line joining $A(5,-6);B(2,-7)$ is $\frac{-7+6}{2-5}=\frac{1}{3}$
Slope of a line perpendicular to another line of slop $m$ is $-\frac{1}{m}$
So, slope of line perpendicular to $AB$ is $-\frac{1}{\frac{1}{3}}=-3$