Ответ:

  1. −13·26⁻¹ = −13/26 = −1/2.
  2. −6·3⁻³ = −6/27 = −2/9.
  3. 81·3⁻⁵ = 3⁴·3⁻⁵ = 3⁻¹ = 1/3.
  4. 16·(2⁻³)² = 2⁴·2⁻⁶ = 2⁻² = 1/4.
  5. (7⁻⁶·7⁻⁸)/7¹³ = 7⁻¹⁴/7¹³ = 7⁻²⁷ = 1/7²⁷.
  6. 27⁻³:9⁻⁴ = (3³)⁻³:(3²)⁻⁴ = 3⁻⁹:3⁻⁸ = 3⁻¹ = 1/3.
  7. (81⁻⁵·9⁻⁸)/27⁻¹¹ = ((3⁴)⁻⁵·(3²)⁻⁸)/(3³)⁻¹¹ = 3⁻³⁶/3⁻³³ = 3⁻³ = 1/27.