Question

Let $A(4,3)$ and $B(6,4)$ be two points, find the slope of a line which is perpendicular to $AB$.

Answer 1

Let m be the slope of AB, Then,
$m=\frac{4-3}{6-4}=\frac{1}{2}$
Now, the slope of a line perpendicular to AB is
$\frac{-1}{m}=-2$