The joint equation of two lines passing through the origin and perpendicular to the lines given by $2 x^2+5…

The joint equation of two lines passing through the origin and perpendicular to the lines given by $2 x^2+5 x y+3 y^2=0$ is
  1. $3 x^2+5 x y+2 y^2=0$
  2. $3 x^2-5 x y+2 y^2=0$
  3. $3 x^2-5 x y-2 y^2=0$
  4. $2 x^2-5 x y+3 y^2=0$

Solution

$2 x^2+5 x y+3 y^2=0 \Rightarrow(x+y)(2 x+3 y)=0$ lines are $x+y=0$ and $2 x+3 y=0$ so, perpendicular lines are $x-y=0$ and $3 x-2 y=0$ joint equation $(x-y)(3 x-2 y)=0$ $\Rightarrow 3 x^2-5 x y+2 y^2=0$

Asked in: MHT CET 2022 (07 Aug Shift 1)

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