Q. The equation ${12x}^{2} + 7xy + {ay}^{2} + 13x - y + 3 = 0$ represents a pair of perpendicular lines. Then, the value of $'a'$ is
A) $\frac{7}{2}$
B) $- 19$
C) $- 12$
D) 12
Explanation
(c)
On comparing the given equation with standard equation, we get $a = 12$ and $b = a$, for perpendicular lines coefficient of $x^{2} +$ coefficient of $y^{2} = 0$
$\therefore\ 12 + a = 0\ \Rightarrow \ a = - 12$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.