1)

If log2(a21)log2(a+1)=3, find the value of a.


A) 9

B) 8

C) 7

D) 6

Answer:

Option A

Explanation:

log2(a21)log2a+1

=log2(a21)a+1

=log2(a+1)(a1)a+1

=log2a1

Given, log2a1=3

ie 23=a1

8 = a-1

a = 9