Question

The equation of line passing through the point $(1,2)$ and perpendicular to the line $x+y+1=0$

• A. $y-x+1=0$
• B. $y-x-1=0$
• C. $y-x+2=0$
• D. $y-x-2=0$

Answer 1

The correct option is B $y-x-1=0$

Equation of the line perpendicular to the line $x+y+1=0$ is $x-y+c=0$ Since this line passes to $(1,2)$

So,

$1-2+c=0$

$-1+c=0$

$c=1$

Hence required equation of the line is

$x-y+1=0$

$\Rightarrow y-x-1=0$