simplify

[ x^(1/3)  - a^(1/3)]  / [ x - a ]  ........factor the denominator as a difference of cubes......assuming that x and a are both positive

[ x^1/3  - a^1/3] / [ (x^(1/3) - a^(1/3))(x^(2/3) + (ax)^1/3 + a^(2/3)) ]  =

1 / [ x^(2/3) + (ax)^1/3 + a^(2/3) ]

Whether or not this is more "simple" is debatablle.......