\[\boxed{\mathbf{609}.}\]
\[1)\ \sqrt{x^{2} + 2} + \sqrt{x^{3} + x^{2}} = 0;\]
\[Первое\ слагаемое:\]
\[\sqrt{x^{2} + 2} = 0;\]
\[x^{2} + 2 = 0;\]
\[x^{2} = - 2 - нет\ корней.\]
\[Второе\ слагаемое:\]
\[\sqrt{x^{3} + x^{2}} = 0;\]
\[x^{3} + x^{2} = 0;\]
\[x^{2} \bullet (x + 1) = 0;\]
\[x_{1} = 0\ \ и\ \ x_{2} = - 1.\]
\[Ответ:\ \ корней\ нет.\]
\[2)\ \sqrt[3]{1 + x^{4}} = \sqrt[3]{1 + x^{2}};\]
\[1 + x^{4} = 1 + x^{2};\]
\[x^{4} - x^{2} = 0;\]
\[x^{2} \bullet \left( x^{2} - 1 \right) = 0;\]
\[(x + 1) \bullet x^{2} \bullet (x - 1) = 0;\]
\[x_{1} = - 1,\ \ \ x_{2} = 0,\ \ \ x_{3} = 1.\]
\[Ответ:\ \ x_{1} = \pm 1;\ \ x_{2} = 0.\]