I've banged my head senseless on an exponential equation lately. I can't seem to solve however i try. Any help would be appreciated.

problem:

4^2x - 4^x = 8 * 4^(x+3)

solve for x

(Headbang)

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- Aug 2nd 2009, 04:25 AMbaelExponential equation
I've banged my head senseless on an exponential equation lately. I can't seem to solve however i try. Any help would be appreciated.

problem:

4^2x - 4^x = 8 * 4^(x+3)

solve for x

(Headbang) - Aug 2nd 2009, 04:55 AMflyingsquirrel
- Aug 2nd 2009, 04:59 AMCaptainBlack
Lets assume the equation is:

$\displaystyle 4^{2x}-4^x=8 \times 4^{x+3}$

or:

$\displaystyle 4^{2x}-4^x=8 \times 4^3 \times 4^{x}$

rearrange:

$\displaystyle (4^{x})^2-513\times 4^x=4^x(4^x-513)=0$

so either $\displaystyle 4^x=0$ which is impossible or:

$\displaystyle

4^x=513

$

and you should be able to finish this yourself from that.

CB - Aug 2nd 2009, 05:02 AMartvandalay11
- Aug 2nd 2009, 05:13 AMbael
thanks a lot to all of you. I think I've been everything except this solution, thank you for opening my eyes!!(Clapping)