Question

If $2x+3y+12=0$ and $x-y+4\lambda =0$ are conjugate with respect to the parabola $y^2=8x$, then $\lambda$ is equal to

• A. 2
• B. -2
• C. 3
• D. -3

Answer 1

Answer: (D)

If $2x+3y+12=0$ and $x-y+4\lambda =0$
are conjugate with respect to parabola $y^2=8x$ then $\lambda$ is equal to :
$1_{1}x+m_{1}y+n_1=0$
$l_{2}x+m_{2}y+n_2=0$
Are conjugate with respect to parabola $y^2=4ax$
$l_l{n}_2+l_2{n}_1=2a{m}_1{m}_2$
$8\lambda +12=-12$
$\lambda =-3$