Answer
$\frac{y^{12}}{3x^{8}}$
Work Step by Step
Start with given expression: $\frac{10x^{4}y^{9}}{30x^{12}y^{-3}}$
Separate fractions with like terms: $\frac{10}{30}\times\frac{x^{4}}{x^{12}}\times\frac{y^{9}}{y^{-3}}$
Divide and use quotient rule on fractions: $\frac{1}{3}x^{-8}y^{12}$
Use negative exponent rule to simplify: $\frac{y^{12}}{3x^{8}}$