ГДЗ по алгебре 7 класс Макарычев ФГОС Задание 965

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\[\textbf{а)}\ x³ - x = 0\]

\[x\left( x^{2} - 1 \right) = 0\]

\[x = 0\ \ \ \ или\ \ \ \ x^{2} - 1 = 0\]

\[\text{\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ }(x - 1)(x + 1) = 0\]

\[\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ x = 1\ \ \ или\ \ \ x = - 1\ \]

\[Ответ:x = 0;x = 1;x = - 1.\]

\[\textbf{б)}\ 9x - x^{3} = x\left( 9 - x^{2} \right) = 0\]

\[x = 0\ \ \ \ \ \ \ \ \ или\ \ \ \ \ \ \ 9 - x^{2} = 0\]

\[\text{\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ }(3 - x)(x + 3) = 0\]

\(x = 3\ \ \ \ \ или\ \ \ \ \ \ x = - 3\)

\[Ответ:x = 0;x = \pm 3.\]

\[\textbf{в)}\ x³ + x² = 0\]

\[x^{2}(x + 1) = 0\]

\[x = 0\ \ \ \ \ \ или\ \ \ \ x = - 1\]

\[Ответ:x = 0;\ \ x = - 1.\]

\[\textbf{г)}\ 5x^{4} - 20x^{2} = 0\]

\[5x^{2}\left( x^{2} - 4 \right) = 0\]

\[5x^{2} = 0\ \ \ \ или\ \ \ \ x^{2} - 4 = 0\]

\[x = 0\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \]

\[(x - 2)(x + 2) = 0\]

\[x = 2\ \ \ \ \ или\ \ \ \ \ x = - 2\]

\[Ответ:x = 0;\ \ x = \pm 2.\]