$\frac{ 10{x}^{4}\sqrt{ 5x } }{ \sqrt{ 4{x}^{4} } }$
$\frac{ 10{x}^{4}\sqrt{ 5x } }{ 2{x}^{2} }$
$\frac{ 5{x}^{4}\sqrt{ 5x } }{ {x}^{2} }$
$5{x}^{2}\sqrt{ 5x }$