6. Упростите выражение $$125a^6b^3 \cdot (-0,2a^2b^4)^3$$

$$125a^6b^3 \cdot (-0,2a^2b^4)^3 = 125a^6b^3 \cdot (-0,2)^3(a^2)^3(b^4)^3 = 125a^6b^3 \cdot (-0,008)a^6b^{12} = 125 \cdot (-0,008) \cdot a^6 \cdot a^6 \cdot b^3 \cdot b^{12} = -1 \cdot a^{6+6} \cdot b^{3+12} = \mathbf{-a^{12}b^{15}}$$