Complex Numbers And Quadratic Equations question 741

Question: The number of solutions of $ \frac{\log 5+\log (x^{2}+1)}{\log (x-2)}=2 $ is

Options:

A) 2

B) 3

C) 1

D) None of these

Show Answer

Answer:

Correct Answer: D

Solution:

We have $ \frac{\log 5+\log (x^{2}+1)}{\log (x-2)}=2 $
Þ $ \log {5(x^{2}+1)}=\log {{(x-2)}^{2}}\Rightarrow 5(x^{2}+1)={{(x-2)}^{2}} $
$ \Rightarrow $ $ 4x^{2}+4x+1=0\Rightarrow x=-\frac{1}{2} $ But for $ x=-\frac{1}{2}\log (x-2) $ is not meaningful. Hence it has no root.