\[ 3x \cdot (6x^{10})^3 : (6x^6)^5 \]
\[ = 3x \cdot (6^3 \cdot (x^{10})^3) : (6^5 \cdot (x^6)^5) \]
\[ = 3x \cdot (216 \cdot x^{10 \cdot 3}) : (7776 \cdot x^{6 \cdot 5}) \]
\[ = 3x \cdot (216 \cdot x^{30}) : (7776 \cdot x^{30}) \]
\[ = (3 \cdot 216) x^{1+30} : (7776 x^{30}) \]
\[ = 648 x^{31} : (7776 x^{30}) \]
\[ = \frac{648}{7776} \cdot x^{31-30} \]
\[ = \frac{1}{12} x^1 \]
\[ = \frac{x}{12} \]
\[ \frac{60}{12} = 5 \]
Ответ: 5