Question

Equation of line passing through the point $(1,2)$ and perpendicular to the line $y=3x-1$ is

• A. $x+3y-7=0$
• B. $x+3y+7=0$
• C. $x+3y=0$
• D. $x-3y=0$

Answer 1

Answer: (A)

Given line is
$y=3x-1$
$\therefore$ Slope of the given line $=3$
$\therefore$ Slope of a line perpendicular to the given line $=-\frac{1}{3}$
$\therefore$ Equation of required line will be
$y-2=\frac{-1}{3}(x-1)$
$\Rightarrow 3y-6=-x+1$
$\Rightarrow x+3y-7=0$