Hello extraordinarymachine Originally Posted by
extraordinarymachine help please, i'm not sure how to solve this question. i know i need to use change of base, but i'm still confused.
solve equation, check for extraneous roots
2^x + 12(2)^-x = 7
Multiply both sides by $\displaystyle 2^x$ and re-arrange:$\displaystyle (2^x)^2-7.2^x+12=0$
$\displaystyle \Rightarrow (2^x-3)(2^x-4)=0$
Can you complete it now?
Grandad