упростите: а) (3/4a^3b^-2)^3 , б) (7m^3n^-3/36xy^-3)^-2​

а)(3/4а³b-²)³=(3/4a²×1/b²)³=(3a³/4b²)³=27a⁹/64b⁶

б)(7m³n-³/36xy-³)-²=(36xy-³/7m³n-³)²=(36x/7m³n-³y³)²=(36xn³/7m³y³)²=(36n³x/7m³y³)²=1296n⁶x²/49m⁶y⁶