Ответ:

  1. \(1.3^{-118}\cdot1.3^{127}=1.3^{-118+127}=1.3^9\approx10.60\).

  2. \(0.87^{-74}:0.87^{-80}=0.87^{-74-(-80)}=0.87^6\approx0.43\).

  3. \(\left(\frac{17}{19}\right)^{-47}:\left(\frac{17}{19}\right)^{-51}=\left(\frac{17}{19}\right)^4\approx0.64\).

  4. \(\left(\frac{23}{21}\right)^{56}\cdot\left(\frac{23}{21}\right)^{-52}=\left(\frac{23}{21}\right)^4\approx1.44\).

Ответ: 1) 10,60; 2) 0,43; 3) 0,64; 4) 1,44.