Step 1 :Given the equation \(16^{6x} = 11^{-x-3}\), we can take the natural logarithm of both sides to get \(\ln(16^{6x}) = \ln(11^{-x-3})\).
Step 2 :Simplifying the equation gives \(6x \cdot \ln(16) = (-x-3) \cdot \ln(11)\).
Step 3 :Solving for x, we get \(x = -\log\left(\frac{11^3}{16^6}\right)\).
Step 4 :So, the final answer is \(x = \boxed{-\log\left(\frac{11^3}{16^6}\right)}\).