This is how I would simplify:
Another approach:
(x^{-3}+ y^{-3}) / (x^{-2} – x^{-1} y^{-1} + y^{-2})
the answer is (x + y) / xy .
p.s '/' indicated fraction.
I tried it for almost 45 minutes but stuck at the last part.
I get this : [x+y (x^{2}-xy-y^{2})] / [xy (x^{2}+y^{2})]
This is my first post so please prove this forum worth staying !!!