\[ (3x)^4 = 3^4 \cdot x^4 = 81x^4 \]
\[ 81x^4 \cdot x^6 = 81x^{4+6} = 81x^{10} \]
\[ \frac{81x^{10}}{x^{-3}} = 81x^{10 - (-3)} = 81x^{10+3} = 81x^{13} \]
\[ 81x^{13} \cdot 10x^5 = (81 \cdot 10) \cdot (x^{13} \cdot x^5) = 810x^{13+5} = 810x^{18} \]
Ответ: 810x18