So the answer in the back is x=2, I also got this as one of two answers - the other being x=3/5. Any ideas apart from David Rayner and Paul Williams being a pair of pricks?
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ln(5x+6) = 2ln(5x-6) Wrong answer in textbook?? watch
- Thread Starter
- 28-02-2016 14:25
- 28-02-2016 14:28
Edit: Having thought about it, I guess you could take lns of a negative thing. If ln(ab) = ln(a) + ln(b) then I guess ln(-x) = ln(x) + ln(-1), and because we know e^ipi=-1, then ln(-1) would be ipi. But regardless, that still means x=3/5 wouldn't be an answerLast edited by Luke Kostanjsek; 28-02-2016 at 16:42.
- 28-02-2016 14:35
Perform steps to make them no longer ln.
- 28-02-2016 16:35
But yes, it's only x = 2