\[\boxed{\text{966.}\text{\ }еуроки - ответы\ на\ пятёрку}\]
\[\textbf{а)}\ x³ + x = 0\]
\[x\left( x^{2} + 1 \right) = 0\]
\[x = 0\ \ \ или\ x^{2} + 1 =\]
\[= 0 \Longrightarrow неверно\ при\ любом\ x.\]
\[Ответ:x = 0.\]
\[\textbf{б)}\ x³ - 2x^{2} = 0\]
\[x^{2}(x - 2) = 0\]
\[x = 0\ \ \ или\ \ \ x = 2\]
\[Ответ:x = 0;\ \ x = 2.\]