Giải các phương trình :
$\begin{array}{l}
1)\,\,{2^{x + 2}}{.5^{x + 2}} = {2^{3x}}{.5^{3x}}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,3)\,\,{3^{2x + 3}}{.5^{2x + 3}} = {3^{5x}}{.5^{5x}}\\
2)\,\,{3^{x + 3}}{.7^{x + 3}} = {3^{2x}}{.7^{2x}}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, 4)\,{2^{x + 4}}{.7^{x + 4}} = {2^{3x}}{.7^{3x}}
\end{array}$