Find the value of \(x\) for which \(3(2^{1-x}) = 7^x\). Give your answer in the form \(\frac{\ln a}{\ln b}\), where \(a\) and \(b\) are integers.
Solution
Start with the equation \(3(2^{1-x}) = 7^x\).
Take the natural logarithm of both sides: \(\ln(3(2^{1-x})) = \ln(7^x)\).
Using the logarithm properties, this becomes \(\ln 3 + (1-x)\ln 2 = x\ln 7\).
Rearrange to form a linear equation: \(\ln 3 + \ln 2 - x\ln 2 = x\ln 7\).
Combine terms: \(\ln 3 + \ln 2 = x\ln 7 + x\ln 2\).
Factor out \(x\): \(\ln 3 + \ln 2 = x(\ln 7 + \ln 2)\).
Solve for \(x\): \(x = \frac{\ln 3 + \ln 2}{\ln 7 + \ln 2}\).
Simplify: \(x = \frac{\ln 6}{\ln 14}\).
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