ГДЗ по алгебре и начала математического анализа 10 класс Колягин Задание 390

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Тип:учебник

Задание 390

\[\boxed{\mathbf{390}.}\]

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

\[- 4x - 3 = 0\]

\[x^{4} + 4x^{3} + 4x^{2} - 2x^{2} -\]

\[- 4x - 3 = 0\]

\[x^{4} + 4x^{3} + 2x^{2} - 4x - 3 = 0\]

\[Делители:\ \pm 1;\ \pm 3.\]

\[1\] \[4\] \[2\] \[- 4\] \[- 3\]
\[1\] \[1\] \[5\] \[7\] \[3\] \[0\]
\[- 1\] \[1\] \[4\] \[3\] \[0\]
\[- 1\] \[1\] \[3\] \[0\]

\[P(x) =\]

\[= (x - 1)(x + 1)^{2}(x - 3) = 0.\]

\[Ответ:x = \pm 1;\ \ 3.\]

\[2)\ \left( x^{2} - x - 3 \right)\left( x^{2} - x - 2 \right) =\]

\[= 12\]

\[t = x^{2} - x:\]

\[(t - 3)(t - 2) = 12\]

\[t^{2} - 3t - 2t + 6 - 12 = 0\]

\[t^{2} - 5t - 6 = 0\]

\[t_{1} + t_{2} = 5;\ \ \ t_{1} \cdot t_{2} = - 6\]

\[t_{1} = - 1;\ \ t_{2} = 6.\]

\[1)\ x^{2} - x = - 1\]

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

\[D = 1 - 4 < 0\]

\[нет\ корней.\]

\[2)\ x^{2} - x = 6\]

\[x^{2} - x - 6 = 0\]

\[x_{1} + x_{2} = 1;\ \ x_{1} \cdot x_{2} = - 6\]

\[x_{1} = 3;\ \ \ x_{2} = - 2.\]

\[Ответ:x = - 2;\ \ 3.\]

\[3)\ \left( x^{2} + x \right)^{2} + (3x - 1)x^{2} +\]

\[+ 5x(x - 1) = 6\]

\[x^{4} + 2x^{3} + x^{2} + 3x^{3} - x^{2} +\]

\[+ 5x^{2} - 5x - 6 = 0\]

\[x^{4} + 5x^{3} + 5x^{2} - 5x - 6 = 0\]

\[Делители:\ \pm 1;\ \pm 2;\ \pm 3;\ \pm 6.\]

\[1\] \[5\] \[5\] \[- 5\] \[- 6\]
\[1\] \[1\] \[6\] \[11\] \[6\] \[0\]
\[- 1\] \[1\] \[5\] \[6\] \[0\]
\[- 2\] \[1\] \[3\] \[0\]

\[P(x) = (x - 1)(x + 1)\]

\[(x + 2)(x + 3) = 0.\]

\[Ответ:x = - 3;\ - 2;\ \pm 1.\]

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

\[+ 4 = 0\]

\[x^{4} - 5x^{2} - 2x^{3} + 8x + 4 = 0\]

\[x^{4} - 2x^{3} - 5x^{2} + 8x + 4 = 0\]

\[Делители:\ \pm 1; \pm 2; \pm 4.\]

\[1\] \[- 2\] \[- 5\] \[8\] \[4\]
\[2\] \[1\] \[0\] \[- 5\] \[2\] \[0\]
\[- 2\] \[1\] \[- 2\] \[- 1\] \[0\]

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

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

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

\[D_{1} = 1 + 1 = 2\]

\[x = \pm \sqrt{2}.\]

\[Ответ:x = \pm 2;\ \pm \sqrt{2}.\]

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

\[+ 4 \cdot (10x - 1) = 7x^{2}\]

\[x^{4} - 4x^{3} + 4x^{2} - 4x^{3} - 8x +\]

\[+ 40x - 4 - 7x^{2} = 0\]

\[x^{4} - 8x^{3} - 3x^{2} + 32x - 4 = 0\]

\[Делители:\ \pm 1;\ \pm 2;\ \pm 4.\]

\[1\] \[- 8\] \[- 3\] \[32\] \[- 4\]
\[2\] \[1\] \[- 6\] \[- 15\] \[2\] \[0\]
\[- 2\] \[1\] \[- 8\] \[1\] \[0\]

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

\[\left( x^{2} - 8x + 1 \right) = 0\]

\[x^{2} - 8x + 1 = 0\]

\[D_{1} = 16 - 1 = 15\]

\[x = 4 \pm \sqrt{15}.\]

\[Ответ:x = \pm 2;\ 4 \pm \sqrt{15}.\]

\[6)\ \left( x^{2} - 2 \right)^{2} +\]

\[+ x(x - 1)(x + 1) = 1\]

\[x^{4} - 4x^{2} + 4 + x^{3} - x - 1 = 0\]

\[x^{4} + x^{3} - 4x^{2} - x + 3 = 0\]

\[Делители:\ \pm 1;\ \pm 3.\]

\[1\] \[1\] \[- 4\] \[- 1\] \[3\]
\[1\] \[1\] \[2\] \[- 2\] \[- 3\] \[0\]
\[- 1\] \[1\] \[1\] \[- 3\] \[0\]

\[P(x) = (x - 1)(x + 1)\]

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

\[x^{2} + x - 3 = 0\]

\[D = 1 + 12 = 13\]

\[x = \frac{- 1 \pm \sqrt{13}}{2}.\]

\[Ответ:x = \pm 1;\ \frac{- 1 \pm \sqrt{13}}{2}\text{.\ }\]

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