Решение

1. a) $$\frac{7^9 \cdot 7^5}{7^{12}} = \frac{7^{9+5}}{7^{12}} = \frac{7^{14}}{7^{12}} = 7^{14-12} = 7^2 = 49$$
2. б) $$\frac{3^{15}}{3^5 \cdot 3^6} = \frac{3^{15}}{3^{5+6}} = \frac{3^{15}}{3^{11}} = 3^{15-11} = 3^4 = 81$$
3. в) $$\frac{5^{16} \cdot 5^4}{5^{18}} = \frac{5^{16+4}}{5^{18}} = \frac{5^{20}}{5^{18}} = 5^{20-18} = 5^2 = 25$$
4. г) $$\frac{0,6^{12}}{0,6^4 \cdot 0,6^5} = \frac{0,6^{12}}{0,6^{4+5}} = \frac{0,6^{12}}{0,6^9} = 0,6^{12-9} = 0,6^3 = 0,216$$