Answer :
[tex](r^{3})^{-3} [/tex]
[tex] \frac{1}{(r^{3})^{3}} [/tex]
[tex] \frac{1}{(r^{3})(r^{3})(r^{3})} [/tex]
[tex] \frac{1}{r^{9}} [/tex]
[tex] \frac{1}{(r^{3})^{3}} [/tex]
[tex] \frac{1}{(r^{3})(r^{3})(r^{3})} [/tex]
[tex] \frac{1}{r^{9}} [/tex]
