\[\boxed{\text{213.}\text{\ }\text{ОК\ ГДЗ\ -\ домашка\ на\ 5}}\]
\[5x^{6} + 6x^{4} + x^{2} + 4 = 0\]
\[5x^{6} + 6x^{4} + x^{2} = - 4\]
\[так\ как\ \ 5x^{6} \geq 0,\ \]
\[6x^{4} \geq 0\ \]
\[x^{2} \geq 0.\]