Simply cancel the common factor of 5 to get...
[tex] \frac{s^-7}{2s^-9} \ \textgreater \ Apply exponent rule \ \textgreater \ \frac{x^a}{x^b} = x^{a - b} \ \textgreater \ \frac{s^-7}{s^-9} = s^{-7 - (-9)} = s^2 \ \textgreater \ \frac{s^2}{2} [/tex]
Therefore our final answer is.
[tex] \frac{s^2}{2} [/tex]
