$$\left. \begin{array} { l } { \quad \frac { x ^ { 2 } } { 3 } + \frac { 48 } { x ^ { 2 } } = 10 ( \frac { x } { 3 } - \frac { 4 } { x } ) } \end{array} \right.$$
$x=3-\sqrt{21}\approx -1.582575695$
$x=-2$
$x=\sqrt{21}+3\approx 7.582575695$
$x=6$
