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Equation in power

Petrus

Well-known member
Feb 21, 2013
739
Hello MHB,
I am stuck on this equation and don't know what to do, If i take ln it does not work, any advice?
\(\displaystyle 16•4^{-x}=4^x-6\)

Regards,
\(\displaystyle |\pi\rangle\)
 

Bacterius

Well-known member
MHB Math Helper
Jan 26, 2012
644
Try multiplying both sides by $4^x$. You get:
$$16 = (4^x)^2 - 6 \cdot 4^x$$
Now substitute $u = 4^x$. What do you see? :)
 

chisigma

Well-known member
Feb 13, 2012
1,704
Hello MHB,
I am stuck on this equation and don't know what to do, If i take ln it does not work, any advice?
\(\displaystyle 16•4^{-x}=4^x-6\)

Regards,
\(\displaystyle |\pi\rangle\)
Set $4^{x}=y$, then solve for y and finally find $x = \frac{\ln y}{\ln 4}$ ...

Kind regards

$\chi$ $\sigma$
 

Petrus

Well-known member
Feb 21, 2013
739
Hello,
Thanks for the fast respond and help from you both!:) i succed to solve it with correct answer!:)
Regards,
\(\displaystyle |\pi\rangle\)