(-125a^3b^7)^3 (-1/25a^2c^6)^2=(-125^3a^9b^21) (1/625a^4c^12)=-125^3/625 a^9-4 b^21 c^12=-15625 a^5 b^21 c^12
(-125a^3b^7)^3 (-1/25a^2c^6)^2
=(-125^3a^9b^21) (1/625a^4c^12)
=-125^3/625 a^9-4 b^21 c^12
=-15625 a^5 b^21 c^12