Ответ:

  1. \(x^8\cdot x^2=x^{8+2}=x^{10}\).
  2. \(x^8:x^2=x^{8-2}=x^6\).
  3. \((x^{-8})^2=x^{-16}\).
  4. \(\frac{(x^4)^5\cdot x^2}{x^{12}}=\frac{x^{20}\cdot x^2}{x^{12}}=x^{20+2-12}=x^{10}\).

Ответ: 1) \(x^{10}\); 2) \(x^6\); 3) \(x^{-16}\); 4) \(x^{10}\).