Solve the equation

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- Aug 14th 2010, 01:56 AMmastermin346indices problem
Solve the equation

- Aug 14th 2010, 02:30 AMDavidM
I seem to be having trouble working out this one... can someone show me what I did wrong?

The x's cancel eachother out... and I don't know where went wrong.

(By the way, x is a whole number) - Aug 14th 2010, 02:33 AMthorin
Hi, DavdM, log is NOT linear function : log(a+b) is NOT equal to log(a)+log(b).

Here, we can write :

finally, - Aug 14th 2010, 02:44 AMDavidM
- Aug 14th 2010, 02:49 AMthorin
- Aug 14th 2010, 03:01 AMDavidM
Oh i get it.

- Aug 14th 2010, 05:18 AMHallsofIvy
Another way to do it: by the laws of exponents, and . The equation becomes so that . Since , so we have, finally, and x= -2.