Q. If one of the roots of the equation $x^{2} + bx + 3 = 0$ is thrice the other, then $b$ is equal to
A) $\pm 3$
B) $\pm 2$
C) 0
D) $\pm 4$
Explanation
(d)
Let $\alpha$ and $3\alpha$ be the roots of the given equation, then
$\therefore\ \alpha + 3\alpha = 4\alpha = - b$
And $\alpha.3\alpha = 3\alpha^{2} = 3$
$\Rightarrow \ \alpha = \pm 1$
$\therefore\ b = \pm 4$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.