$\begin{array}{l}
 {a^0} = 1 \\ 
 {a^{ - x}} = \frac{1}{a} < 1 \\ 
 {0^{ - x}} = \frac{1}{{{0^x}}} = \frac{1}{0} - nedef. \\ 
 {\left( {\frac{1}{a}} \right)^x} = \frac{1}{{{a^x}}} < 1 \\ 
 {\left( {\frac{1}{a}} \right)^{ - x}} = \frac{1}{{{a^{ - x}}}} = {a^x} > 1 \\ 
 \end{array}$