$$( \frac{ { x }^{ 3 } }{ 3 } + \frac{ 3 }{ 5 } )( \frac{ { x }^{ 3 } }{ 3 } + \frac{ 3 }{ 5 } )$$
$\frac{\left(5x^{3}+9\right)^{2}}{225}$
$\frac{x^{6}}{9}+\frac{2x^{3}}{5}+\frac{9}{25}$
