Q. If each pair of the equation $x^{2} + ax + b = 0,\ x^{2} + bx + c = 0\ and\ x^{2} + cx + a = 0$ has a common root, then product of all common roots is

A) $\sqrt{abc}$
B) $2\sqrt{abc}$
C) $\sqrt{ab + bc + ca}$
D) $2\sqrt{ab + bc + ca}$
Explanation

(a)
Let the roots be $\alpha,\ \beta,\beta,\ \gamma\ and\ \gamma,\ \alpha,$ then
$\alpha\beta = b,\ \beta\gamma = c\ and\ \gamma\alpha = a$
$\Rightarrow \ \alpha\beta\gamma = \sqrt{abc}$

Dr. Abubacker
Reviewed by Dr. Abubacker

Physics Educator & NEET/JEE Specialist

Ph.D. in Physics with 19+ years of teaching experience.