Ответ:

  1. x¹² · x³ = x¹⁵.
  2. a⁻³ · a⁸ = a⁵ = a⁵.
  3. t⁻⁵ · t = t⁻⁴.
  4. y⁴ · y⁻⁴ = 1.
  5. m² : m⁵ = m⁻³ = 1/m³.
  6. n⁻¹² : n⁻⁸ = n⁻⁴ = 1/n⁴.
  7. (s³)⁷ = s²¹.
  8. (x⁻⁴)⁵ = x⁻²⁰.
  9. (k⁻⁷)⁻² = k¹⁴.
  10. (x⁶y)⁻⁴ = x⁻²⁴y⁻⁴.
  11. (a⁻¹/b)⁻³ = b³/a³ = b³/a³.