If the distance between the parallel lines given by the equation $x^2+4 x y+4 y^2+3 x+6y-4=0$ is $\lambda$,…

If the distance between the parallel lines given by the equation $x^2+4 x y+4 y^2+3 x+6y-4=0$ is $\lambda$, then $\lambda^2=$
  1. $5$
  2. $\sqrt{5}$
  3. $25$
  4. $\frac {9}{5}$

Solution

Given equation is $\begin{aligned} & x^2+4 x y+4 y^2+3 x+6 y-4=0 \\ & (x+2 y)^2+3(x+2 y)-4=0 \\ & (x+2 y+4)(x+2 y-1)=0 \end{aligned}$ $\therefore \quad$ The lines are: $x+2 y+4=0$ and $x+2 y-1=0$ $\begin{aligned} \therefore \quad \text { Required distance } & =\frac{|4-(-1)|}{\sqrt{1+4}} \\ & =\frac{5}{\sqrt{5}}=\sqrt{5} \text { units } \end{aligned} $ $\lambda=\sqrt{5}$ units $\lambda^2=5$

Asked in: MHT CET 2023 (09 May Shift 1)

Practice more Straight Lines questions on Aicharya