Ответ:

  1. \(3a\cdot0.5b\cdot4c=(3\cdot0.5\cdot4)abc=6abc\).
  2. \(7x\cdot0.1y\cdot2z=(7\cdot0.1\cdot2)xyz=1.4xyz\).
  3. \(-2\frac23m^4\cdot9mn^3=-\frac83\cdot9\,m^5n^3=-24m^5n^3\).
  4. \(-2\frac13m^2\cdot6mn^3=-\frac73\cdot6\,m^3n^3=-14m^3n^3\).
  5. \(-3a^2b^4\cdot3a^2\cdot b^5=-9a^4b^9\).
  6. \(-4mn^5\cdot5n^2\cdot m^4=-20m^5n^7\).
  7. \((-4a^2b^6)^3=(-4)^3a^6b^{18}=-64a^6b^{18}\).
  8. \((-3m^7n^2)^4=(-3)^4m^{28}n^8=81m^{28}n^8\).

Ответ: 1) \(6abc\); 2) \(1.4xyz\); 3) \(-24m^5n^3\); 4) \(-14m^3n^3\); 5) \(-9a^4b^9\); 6) \(-20m^5n^7\); 7) \(-64a^6b^{18}\); 8) \(81m^{28}n^8\).