Ответ:

  1. \(\frac{27c^2}{5d}\cdot\frac1{-18c^3d^2}=-\frac3{10c d^3}\).
  2. \(\frac{14a^2}{9x^3}\cdot\frac{4x^2}{7a}=\frac{8a}{9x}\).
  3. \(\frac{7x^2}{10a^3}\cdot\frac{15a^5}{x}=\frac{21a^2x}{2}\).
  4. \(27a^3\cdot\frac{a^2}{b^2}\cdot\frac{7b^3}{18a^5}=\frac{21b}{2}\).

Жауап: 1) \(-\frac3{10cd^3}\); 2) \(\frac{8a}{9x}\); 3) \(\frac{21a^2x}{2}\); 4) \(\frac{21b}{2}\).