Originally Posted by
skeeter I meant what you arrived at at your last step ...
$\displaystyle \frac{3}{4}\left(4^{\frac{4}{3}} + 3^{\frac{4}{3}}\right)$
forgot the denominator of 4 under the leading 3
$\displaystyle 4^{\frac{4}{3}} + 3^{\frac{4}{3}}$ cannot be simplified further