Answer:
Property : a^-b = 1/a^b
Using this property, we can rewrite the expression using positive exponents :
[tex]1. \frac{1}{9}*x^{-2} *y^{-1} =\frac{1}{9}\frac{1}{x^{2} } \frac{1}{y} =\frac{1}{9x^{2} y} \\2. a^{-5} a^{-8} =\frac{1}{a^{5}a^{8} } =\frac{1}{a^{13} }[/tex]