# Math Help - exponential equations

1. ## exponential equations

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

2. 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 $2^x$ and re-arrange:
$(2^x)^2-7.2^x+12=0$

$\Rightarrow (2^x-3)(2^x-4)=0$
Can you complete it now?

3. 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.

Originally Posted by extraordinarymachine

solve equation, check for extraneous roots

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

Hi all
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