Answer
$\frac{1}{1000x^{6}}$
Work Step by Step
When a product is raised to a power, raise each factor to that power:
$$(10x^{2})^{-3}$$
$$=10^{-3}x^{(2\times(-3))}$$
$$=10^{-3}x^{-6}$$
Write as a fraction, move the base with the negative exponent to the other side of the fraction, and make the exponent positive:
$$=\frac{1}{10^{3}x^{6}}$$
$$=\frac{1}{1000x^{6}}$$