What is the value of x? A^3a^x = a^12
\small{\text{$ \begin{array}{rcl} A^3a^x &=& a^{12} \\ a^x &=& \dfrac{a^{12}}{A^3} \qquad | \qquad b=\dfrac{a^{12}}{A^3} \\\\ a^x &=& b \qquad | \qquad \ln{()} \\ x\ln{(a)} &=& \ln{(b)}\\\\ \mathbf{x} &\mathbf{=}& \mathbf{\dfrac{ \ln{(b)} }{\ln{(a)} } }\quad $ and $ \mathbf{ \quad b=\dfrac{a^{12}}{A^3} }\\\\ \end{array} $}}}