Answer
$\displaystyle \frac{x^{2}+4}{(x^{2}+3)^{5/3}}$
Work Step by Step
$\left[(x^{2}+3)^{-2/3}=(x^{2}+3)^{-5/3+1}=(x^{2}+3)(x^{2}+3)^{-5/3}\right]$
$(x^{2}+3)^{-2/3}+(x^{2}+3)^{-5/3}=(x^{2}+3)(x^{2}+3)^{-5/3}+(x^{2}+3)^{-5/3}$
... factor out $(x^{2}+3)^{-5/3}$
$=(x^{2}+3)^{-5/3}[(x^{2}+3)+1]$
$=(x^{2}+3)^{-5/3}[x^{2}+4] \qquad $... apply $a^{-n}=\displaystyle \frac{1}{a^{n}}$
$=\displaystyle \frac{x^{2}+4}{(x^{2}+3)^{5/3}}$
