$$\frac{a^9 \cdot a^{12}}{a^{18}} = \frac{a^{9+12}}{a^{18}} = \frac{a^{21}}{a^{18}} = a^{21-18} = a^3$$
При $$a = 4$$:
$$a^3 = 4^3 = 4 \cdot 4 \cdot 4 = 16 \cdot 4 = 64$$
Ответ: 64
$$\frac{a^{12} \cdot a^6}{a^{14}} = \frac{a^{12+6}}{a^{14}} = \frac{a^{18}}{a^{14}} = a^{18-14} = a^4$$
При $$a = 3$$:
$$a^4 = 3^4 = 3 \cdot 3 \cdot 3 \cdot 3 = 9 \cdot 9 = 81$$
Ответ: 81
$$\frac{a^{11} \cdot a^9}{a^{18}} = \frac{a^{11+9}}{a^{18}} = \frac{a^{20}}{a^{18}} = a^{20-18} = a^2$$
При $$a = 7$$:
$$a^2 = 7^2 = 7 \cdot 7 = 49$$
Ответ: 49