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Logarithmic equation 4^x-1 = 3^2x?  TOPIC_SOLVED

This is similar to some other equations which have been solved here, but the "2x" is throwing me, I'm not sure what to do with it. The equation is 4^x-1 = 3^2x, solve for x. I have the answer, but have not been able to reproduce the steps to get to it. log4/(log4)-(2log3), then it is compl...
by danlers
on Tue Aug 23, 2011 12:48 am
 
Forum: Advanced Algebra ("pre-calculus")
Topic: Logarithmic equation 4^x-1 = 3^2x?
Replies: 12
Views: 7543

Re: Logarithmic equation 4^x-1 = 3^2x?  TOPIC_SOLVED

Oops, no, not quite.
4^(x-1) = 3^(2x)
The exponents are x-1 and 2x.
by danlers
on Tue Aug 23, 2011 3:38 am
 
Forum: Advanced Algebra ("pre-calculus")
Topic: Logarithmic equation 4^x-1 = 3^2x?
Replies: 12
Views: 7543

Re: Logarithmic equation 4^x-1 = 3^2x?  TOPIC_SOLVED

Yes, I know how to take the log and expand it, but I am having trouble solving it for x. It seems that everything I do to solve for (x-1) messes up (2x) and vice versa. I'm probably overlooking something obvious.
by danlers
on Tue Aug 23, 2011 8:41 pm
 
Forum: Advanced Algebra ("pre-calculus")
Topic: Logarithmic equation 4^x-1 = 3^2x?
Replies: 12
Views: 7543

Re: Logarithmic equation 4^x-1 = 3^2x?  TOPIC_SOLVED

I've tried to solve this so many ways I don't even know what work to show. Let me ask a specific question. If I start by taking the log of both sides, should I do log (base 4), log (base 3), or log (base 10)?
by danlers
on Wed Aug 24, 2011 12:09 am
 
Forum: Advanced Algebra ("pre-calculus")
Topic: Logarithmic equation 4^x-1 = 3^2x?
Replies: 12
Views: 7543

Re: Logarithmic equation 4^x-1 = 3^2x?  TOPIC_SOLVED

Hmm, I see that. Apparently my problem is further on. Here's one of the ways I've tried it. 4^(x-1) = 3^(2x) log4^(x-1) = log3^(2x) x(log4)-1(log4) = 2x(log3) x(log4)=2x(log3)+(log4) x/2x=(log3)+(log4)/log4 and if I go a step further I would end up with x/x=2(log3)+(log4)/log4 and x/x equals one. I ...
by danlers
on Wed Aug 24, 2011 5:53 am
 
Forum: Advanced Algebra ("pre-calculus")
Topic: Logarithmic equation 4^x-1 = 3^2x?
Replies: 12
Views: 7543

Re: Logarithmic equation 4^x-1 = 3^2x?  TOPIC_SOLVED

By doing it too late at night...
The fact is I don't really know what to do at that point. That's the problem.
by danlers
on Wed Aug 24, 2011 4:01 pm
 
Forum: Advanced Algebra ("pre-calculus")
Topic: Logarithmic equation 4^x-1 = 3^2x?
Replies: 12
Views: 7543

Re: Logarithmic equation 4^x-1 = 3^2x?  TOPIC_SOLVED

Thanks, I got it figured out.
by danlers
on Fri Aug 26, 2011 2:03 pm
 
Forum: Advanced Algebra ("pre-calculus")
Topic: Logarithmic equation 4^x-1 = 3^2x?
Replies: 12
Views: 7543

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