9: The numerator is clear, the leading term is x.
Concerning the denominator, you should have started with individual cubic
roots. Inside there is x2 prevailing over
"+x" and
"-x", so both cubic roots involved in the denominator are of
the type
(x2)1/3 = x2/3.
Using this one observe that all three terms in the denominator are of the
type
(x2/3)2 = x4/3.
This is then the leading term for the denominator, fortunately the terms are
added so there will be no trouble. Factor the dominant terms out and see
what happens.
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