Use logarithms to solve the equation \(4^{3x-1} = 3(5^x)\), giving your answer correct to 3 decimal places.
Solution
Start by taking the natural logarithm of both sides of the equation:
\(\ln(4^{3x-1}) = \ln(3 \cdot 5^x)\)
Apply the logarithm power rule: \(\ln(a^b) = b \ln(a)\).
\((3x-1) \ln 4 = \ln 3 + x \ln 5\)
Expand and rearrange the equation to solve for \(x\):
\(3x \ln 4 - \ln 4 = \ln 3 + x \ln 5\)
\(3x \ln 4 - x \ln 5 = \ln 3 + \ln 4\)
Factor out \(x\):
\(x(3 \ln 4 - \ln 5) = \ln 3 + \ln 4\)
Solve for \(x\):
\(x = \frac{\ln 3 + \ln 4}{3 \ln 4 - \ln 5}\)
Calculate the value of \(x\) to three decimal places:
\(x \approx 0.975\)
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