[tex](\frac{8s^{-3}t^{-2}}{4st^{-1}})^{-1}=[/tex] divide numbers 8/4=2 [tex](\frac{2s^{-3}t^{-2}}{st^{-1}})^{-1}=[/tex] apply rule [tex]a^{-n}=\frac{1}{a^n}[/tex] [tex](\frac{2}{st^{-1}*s^{3}t^{2}})^{-1}=[/tex] sum up the exponents [tex](\frac{2}{s^4t})^{-1}=[/tex] one more negative exponent flip [tex]\frac{1}{\frac{2}{s^4t}}=[/tex] simplify double fraction [tex]\frac{s^4t}{2}[/tex]
