Complex Numbers And Quadratic Equations question 753

Question: The number of solutions of $ {\log_4}(x-1)={\log_2}(x-3) $ [IIT Screening 2001]

Options:

A) 3

B) 1

C) 2

D) 0

Show Answer

Answer:

Correct Answer: B

Solution:

$ {\log_4}(x-1)={\log_2}(x-3) $
$ \Rightarrow x-1={{(x-3)}^{2}} $
$ \Rightarrow x^{2}-7x+10=0 $
$ \Rightarrow (x-5)(x-2)=0 $
$ \therefore x=5, $ 2 but $ x-3<0 $ when $ x=2 $
$ \therefore $ only solution is $ x=5 $
$ \therefore $ Hence number of solution is one.