# Thread: Exponential Equation

1. ## Exponential Equation

Hi,

I'm not sure how to solve this one, I tired getting into quadratic form, but I ended up getting a cubic. :S

4^x + 12(2)^(-x) = 7

2. ## Re:

Originally Posted by millerst
Hi,

I'm not sure how to solve this one, I tired getting into quadratic form, but I ended up getting a cubic. :S

$4^x+12(2)^{-x}=7$
$2^{2x}+12(2)^{-x}=7$

Then multiply both sides by $2^x$

$2^{3x}-7(2^x)+12=0$
Let $2^x$ be a
$a^3-7a+12=0$
Then solve the equation ..