SOLUTION: Solve: 8^(4x-3)= 1/16, find the exact answer.

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Question 34528: Solve:
8^(4x-3)= 1/16, find the exact answer.

Found 2 solutions by venugopalramana, josmiceli:
Answer by venugopalramana(3286)   (Show Source): You can put this solution on YOUR website!
8^(4x-3)= 1/16,
(2^3)^(4X-3)=1/(2^4)=2^(-4)
2^(12X-9)=2^(-4)
12X-9=-4
12X=-4+9=-5
X=-5/12
find the exact answer.

Answer by josmiceli(19441)   (Show Source): You can put this solution on YOUR website!

note that

multiply both sides by 8^3


take log base 10 of both sides

note that





check this by subbing in the original equation
I get
this is true- checks
------------------
note also-



this is a more "exact" answer, since there is no rounding to a certain number
of decimal points

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