6. Упростите выражение 216mn^4 ⋅ (-\frac{1}{6}mn)^3.

216mn^4 ⋅ (-\frac{1}{6}mn)^3 = 216mn^4 ⋅ (-1)^3(\frac{1}{6})^3m^3n^3 = 216mn^4 ⋅ -\frac{1}{216}m^3n^3 = -m^4n^7.