To solve the equation \(-3 e^{-9x} = -57\), we can follow these steps:
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Divide both sides by -1 to eliminate the negative signs: \[ 3 e^{-9x} = 57 \]
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Divide both sides by 3: \[ e^{-9x} = \frac{57}{3} \] \[ e^{-9x} = 19 \]
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Take the natural logarithm (ln) of both sides to solve for \(x\): \[ \ln(e^{-9x}) = \ln(19) \]
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Use the property of logarithms \(\ln(e^a) = a\): \[ -9x = \ln(19) \]
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Divide both sides by -9 to isolate \(x\): \[ x = \frac{-\ln(19)}{9} \]
That's the solution for \(x\): \[ x = -\frac{\ln(19)}{9} \]