Solve for X

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• May 17th 2010, 07:10 PM
advancedfunctions2010
Solve for X
9 = 40(2)^2x+1
• May 17th 2010, 07:36 PM
harish21
Quote:

Originally Posted by advancedfunctions2010
9 = 40(2)^2x+1

Your notation is very confusing. Please write it clearly
• May 17th 2010, 08:04 PM
AllanCuz
Quote:

Originally Posted by harish21
Your notation is very confusing. Please write it clearly

I think he wants,

$9 = 40(2)^{2x+1 }$

In which case we use basic logs.

$ln ( \frac{ 9}{40} ) = ln (2^{2x+1}) = (2x+1) ln2$

$\frac { ln ( \frac{ 9}{40} ) }{ ln2} = 2x + 1$

$\frac { ln ( \frac{ 9}{40} ) }{2 ln2} - \frac{1}{2} = x$