Which of the given numbers is the product of all the solutions of the following exponential equations?
\begin{align*} 3^x+3^{x+2}&=30\\ 3^{x+1}+3^{x-1}&=\frac{10}9 \end{align*}
The following exponential equation has solutions \( x_1 \) and \( x_2 \). Find the sum of \( x_1 \) and \( x_2 \).
\[ \frac{4^{x^2 }}{16^{x+1}} =16\cdot4^x \]