1. equation for x

solve equation for x:

12^(x - 7) =
7

2. The inverse function of exponentiation is a logarithm.

3. thanks, but i'm still unfamiliar with what you mean.

4. Originally Posted by darkblue
thanks, but i'm still unfamiliar with what you mean.
Hi darkblue,

This is what he means.

Take the natural log of both sides and use this:

$\ln a^r=r \ln a$,

$12^{x-7}=7$

$\ln 12^{x-7}=\ln 7$

$(x-7)\ln 12=\ln 7$

$x-7=\frac{\ln 7}{\ln 12}$

$x=\frac{\ln 7}{\ln 12}+7$

5. thankyou so much!!
it is much easier to understand when i have a visual.