Solve the equation accurate to three decimal places.
Divide both sides by 3.
\(8^{x-4} = \frac{38}{3}\)
Take the natural logarithm of both sides.
\(\ln(8^{x-4}) = \ln\left(\frac{38}{3}\right)\)
Use the power rule of logarithms.
\((x-4)\ln(8) = \ln\left(\frac{38}{3}\right)\)
Solve for x.
\(x-4 = \frac{\ln\left(\frac{38}{3}\right)}{\ln(8)}\)
Calculate the value of x.
\(x = \frac{\ln\left(\frac{38}{3}\right)}{\ln(8)} + 4\)
\(\boxed{x \approx 5.221}\)
Find the derivative of the function.
Rewrite the function using exponentials.
\(y = e^{\ln(2^{-3x})}\)
Simplify the expression.
\(y = e^{-3x\ln(2)}\)
Apply the chain rule.
\(y' = e^{-3x\ln(2)} \cdot (-3\ln(2))\)
Substitute back to the original base.
\(y' = -3\ln(2) \cdot 2^{-3x}\)
\(\boxed{y' = -3\ln(2) \cdot 2^{-3x}}\)
\(\boxed{x \approx 5.221}\)
\(\boxed{y' = -3\ln(2) \cdot 2^{-3x}}\)