27. Вычисли устно: 3³; −3³; 3⁴; (−3)⁴; −3⁴; 1⁸; (−1)⁸; (0,3)²; (0,3)³; (−2/5)³; (1 1/4)²; 20⁴·(1/10)⁴; 10⁸/(2⁶·5⁶); 14⁵/7⁵.

\(3^3=27\); \(-3^3=-27\); \(3^4=81\); \((-3)^4=81\); \(-3^4=-81\); \(1^8=1\); \((-1)^8=1\); \((0.3)^2=0.09\); \((0.3)^3=0.027\); \(\left(-\frac25\right)^3=-\frac8{125}\); \(\left(1\frac14\right)^2=\frac{81}{16}=5\frac1{16}\); \(20^4\cdot\left(\frac1{10}\right)^4=16\); \(\frac{10^8}{2^6\cdot5^6}=100\); \(\frac{14^5}{7^5}=32\).