\[ (7x)^2 = 7^2 \cdot x^2 = 49x^2 \]
\[ 49x^2 \cdot x^{-10} = 49x^{2+(-10)} = 49x^{-8} \]
\[ \frac{49x^{-8}}{10x^3} = \frac{49}{10} \cdot x^{-8 - 3} = \frac{49}{10} x^{-11} \]
Ответ: \(\frac{49}{10} x^{-11}\) или \(\frac{49}{10x^{11}}\)