3. Упростите: 1) (13x⁻⁴/y⁻⁵) · (y/(52x⁻⁶)); 2) (21a⁻⁴/(10b⁹)) · (15b⁻⁶/(7a⁻⁸)).

1. \(\frac{13x^{-4}}{y^{-5}}\cdot\frac{y}{52x^{-6}}=\frac{13}{52}x^{-4-(-6)}y^{5+1}=\frac{1}{4}x^2y^6=\frac{x^2y^6}{4}\).
2. \(\frac{21a^{-4}}{10b^9}\cdot\frac{15b^{-6}}{7a^{-8}}=\frac{21\cdot15}{10\cdot7}a^{-4-(-8)}b^{-9-6}=\frac{9}{2}a^4b^{-15}=\frac{9a^4}{2b^{15}}\).

Ответ: 1) x²y⁶/4; 2) 9a⁴/(2b¹⁵).