a − n = 1 a n {\displaystyle \ a^{-n}={1 \over a^{n}}\ }
a − 5 = 1 a 5 5 − a = 1 5 a 5 3 = 1 5 − 3 5 b − a = 1 5 − b + a {\displaystyle \ a^{-5}={1 \over a^{5}}\qquad 5^{-a}={1 \over 5^{a}}\qquad 5^{3}={1 \over 5^{-3}}\qquad 5^{b-a}={1 \over 5^{-b+a}}}
1 6 x = 6 − x {\displaystyle \quad {\frac {1}{6^{x}}}=6^{-x}\quad } 3 b 7 = 3 b − 7 {\displaystyle \quad {\frac {3}{b^{7}}}={3}b^{-7}\quad } 5 z − d = 5 z d {\displaystyle \quad {\frac {5}{z^{-d}}}=5\ z^{d}\quad }
