Question

Find the slope of a line perpendicular to a line x+3y+1 = 0 and passing through (5, 12).
$\left[2Marks\right]$

Answer 1

Product of the slopes of any two perpendicular lines is -1.
$\left[1Mark\right]$
Slope of a line of the equation ax + by + c = 0 is $-\frac{a}{b}$.
So, slope of the given line x+3y+1=0 is $-\frac{1}{3}$.
Let the slope of the required line be 'm'.
$m\times -\frac{1}{3}=-1\to m=3$.
$\left[1Mark\right]$