(4/5a³b¹²)^-3 ∙ (5a⁹b¹⁷)⁻² = (5/4a⁻³b⁻¹²)^3 * (1/(5a⁹b¹⁷))² = (125a⁹b³⁶) / 64 * 1/(25a¹⁸b³⁴) = (125a⁹b³⁶) / (64*25a¹⁸b³⁴) = 5b²/ (64 a⁹)
Ответ: 5b²/(64a⁹)