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Log Problem

Date: 5 May 1995 14:00:34 -0400
From: Harvey Robicheau
Subject: Home work with logs

 Solve: 3(3^x)+9(3^-x) = 28

Harvey J. Robicheau
soccer coach Naches Valley High School
Box 463 Naches,Washington 98937

Date: 5 May 1995 14:30:28 -0400
From: Dr. Ken
Subject: Re: Home work with logs

Hello there!

The first thing I think I'd do is lump the 3 and the 9 into the exponential
terms like this: 3(3^x)+9(3^-x) = 3^(x+1) + 3^(2-x) = 28

Now, to be honest, I think the easiest way to proceed from here is just by
inspection.  Can you come up with two powers of 3 that add up to 28?  If 
you can, then see if you can get x-1 to be one power and 2-x to be the 
other. If you're still stuck, don't hesitate to write us back.  Thanks!

Associated Topics:
High School Exponents

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