Olympiad Maths Prep

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Problem 257

AMC 10/12, early questions
Algebra Difficulty 4.0 Find the answer 7. tekmovanje v znanju matematike za dijake srednjih tehniških in strokovnih šol · Slovenia

Problem:

Reši enačbo log3(log2x+12)+2=4\log_{3}(\log_{2} x + 12) + 2 = 4 in rešitev zapiši v obliki ulomka.

Official solution

Solution:

Enačbo najprej uredimo log3(log2x+12)=2\log_{3}(\log_{2} x + 12) = 2. Upoštevamo definicijo logaritma in zapišemo 32=log2x+123^{2} = \log_{2} x + 12. Enačbo ponovno uredimo in dobimo log2x=3\log_{2} x = -3. Rešimo 23=x2^{-3} = x. Rešitev je x=18x = \frac{1}{8}.

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