\[\frac{49^{5} \cdot 7^{12}}{343^{7}} = \frac{\left( 7^{2} \right)^{5} \cdot 7^{12}}{\left( 7^{3} \right)^{7}} =\]
\[= \frac{7^{10} \cdot 7^{12}}{7^{21}} = \frac{7^{22}}{7^{21}} = 7^{1} = 7.\]