Solve log.

Question

2 log (x-1)= log (x+1)

the answer is 3 but i don't know how to get it...Any one hint or suggestion will be greatly appreciated :)

Answer 1

From previous ans:

2 log (x-1)= log (x+1)
log[(x-1)²] = log(x+1)
Take antilog:
(x-1)²=x+1
Expand and solve quadratic:
x²-3x=0
x(x-3)=0

x=0 is not admissible as solution because log(-1) is undefined.
The remaining answer is therefore x=3.