5) 6¹² ⋅ (6³)⁵ (6⁵)⁴ ⋅ 6⁴;

5) $$\frac{6^{12} \cdot (6^3)^5}{(6^5)^4 \cdot 6^4} = \frac{6^{12} \cdot 6^{15}}{6^{20} \cdot 6^4} = \frac{6^{12+15}}{6^{20+4}} = \frac{6^{27}}{6^{24}} = 6^{27-24} = 6^3$$

Ответ: 6³