Ответ:

  1. а) \(\frac{8}{15a^2b^3}\cdot\frac{3}{10a^3b^2}=\frac{24}{150a^5b^5}=\frac{4}{25a^5b^5}\).
  2. б) \(\frac{7n+m}{63m^2n^4}\cdot\frac{n-4m}{36m^3n^3}=\frac{(7n+m)(n-4m)}{2268m^5n^7}\).
  3. в) \(\frac{11c}{28p^3q^3}\cdot\frac{4c}{35p^4q}=\frac{44c^2}{980p^7q^4}=\frac{11c^2}{245p^7q^4}\).
  4. г) \(\frac{2y^2-x}{24x^2y^3}\cdot\frac{8y+5x^2}{60x^4y}=\frac{(2y^2-x)(8y+5x^2)}{1440x^6y^4}\).

Ответ: а) \(\frac{4}{25a^5b^5}\); б) \(\frac{(7n+m)(n-4m)}{2268m^5n^7}\); в) \(\frac{11c^2}{245p^7q^4}\); г) \(\frac{(2y^2-x)(8y+5x^2)}{1440x^6y^4}\).