Question 1160441
<pre>

{{{
(x^3 - y^3)(x^(-3) + y^(-3))}}}
{{{
x^3*x^(-3)+x^3y^(-3)-x^(-3)y^3 - y^3y^(-3)}}}
{{{
x^(3-3)+x^3(1^""/y^3)-(1^""/x^3)y^3 - y^(3-3)}}}
{{{
x^0+x^3/y^3-y^3/x^3 - y^0}}}
{{{
1+x^3/y^3-y^3/x^3 - 1}}}
{{{
x^3/y^3-y^3/x^3}}}

I personally think the above is the simplest answer.  But your
teacher may intend for you to keep going:

{{{
(x^6-y^6)/(x^3y^3)}}}
{{{
(x^3-y^3)(x^3+y^3)/(x^3y^3)}}}
{{{
(x^""-y)(x^2+xy+y^2)(x^""+y)(x^2-xy+y^2)/(x^3y^3)}}}
{{{
(x^""-y)(x^""+y)(x^2+xy+y^2)(x^2-xy+y^2)/(x^3y^3)}}}

Edwin</pre>