Ответ:

  1. \(15x^2\cdot\frac{7}{6x^3}=\frac{105x^2}{6x^3}=\frac{35}{2x}\).
  2. \(\frac{25}{16y^2}\cdot2y^2=\frac{50y^2}{16y^2}=\frac{25}{8}\).
  3. \(6am^2\cdot\frac{4a}{3m^3}=\frac{24a^2m^2}{3m^3}=\frac{8a^2}{m}\).
  4. \(\frac{2b}{5a^3}\cdot10a^2=\frac{20a^2b}{5a^3}=\frac{4b}{a}\).

Ответ: а) \(\frac{35}{2x}\); б) \(\frac{25}{8}\); в) \(\frac{8a^2}{m}\); г) \(\frac{4b}{a}\).