Question:
Let $\alpha$ and $\beta$ be the roots of $x^{2}-3 x+p=0$ and $\gamma$ and $\delta$ be the roots of $x^{2}-6 x+q=0$. If $\alpha, \beta, \gamma, \delta$ form a geometric progression. Then ratio $(2 q+p):(2 q-p)$ is :
Correct Option: , 2
Solution:
Let $\alpha, \beta, \gamma, \delta$ be in G.P., then $\alpha \delta=\beta \gamma$
$\Rightarrow \frac{\alpha}{\beta}=\frac{\gamma}{\delta} \Rightarrow\left|\frac{\alpha-\beta}{\alpha+\beta}\right|=\left|\frac{\gamma-\delta}{\gamma+\delta}\right|$
$\Rightarrow \frac{\sqrt{9-4 p}}{3}=\frac{\sqrt{36-4 q}}{6}$
$\Rightarrow 36-16 p=36-4 q \Rightarrow q=4 p$
$\therefore \frac{2 q+p}{2 q-p}=\frac{8 p+p}{8 p-p}=\frac{9 p}{7 p}=\frac{9}{7}$