Решебник по алгебре 9 класс Макарычев Задание 30

 

\[\boxed{\text{30\ (30).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]

\[\textbf{а)}\ 6x^{2} - 3x = 0\]

\[3x(2x - 1) = 0\]

\[3x = 0;\ \ \ \ \ \ 2x - 1 = 0\]

\[x = 0\ \ \ \ \ \ \ \ \ \ 2x = 1\]

\[\text{\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ }x = \frac{1}{2} = 0,5.\]

\[Ответ:x = 0;x = 0,5.\]

\[\textbf{б)}\ x^{2} + 9x = 0\]

\[x(x + 9) = 0\]

\[x = 0;\ \ \ \ \ \ \ \ x + 9 = 0\]

\[x_{1} = 0\ \ \ \ \ \ \ \ x_{2} = - 9.\]

\[Ответ:x = 0;x = - 9.\]

\[\textbf{в)}\ x^{2} - 36 = 0\]

\[x^{2} = 36\]

\[x = \pm \sqrt{36}\]

\[x = \pm 6.\]

\[Ответ:x = \pm 6.\]

\[\textbf{г)}\ 5x^{2} + 1 = 0\]

\[5x^{2} = - 1\ \]

\[x^{2} = - \frac{1}{5} \Longrightarrow корней\ нет.\]

\[Ответ:решений\ нет.\]

\[\textbf{д)}\ 0,5x^{2} - 1 = 0\]

\[0,5x^{2} = 1\]

\[x^{2} = \frac{1}{0,5} = \frac{10}{5}\]

\[x^{2} = 2\]

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

\[Ответ:x = \pm \sqrt{2}.\]

\[\textbf{е)}\ 0,6x + 9x^{2} = 0\]

\[9x \cdot \left( x + \frac{6}{90} \right) = 0\]

\[9x = 0;\ \ \ \ \ \ \ x + \frac{1}{15} = 0\]

\[x = 0\ \ \ \ \ \ \ \ \ \ x = - \frac{1}{15}.\]

\[Ответ:x = 0;\ \ x = - \frac{1}{15}.\]

\[\boxed{\text{30.\ }\text{ОК\ ГДЗ\ -\ домашка\ на\ 5}}\]

\[1 < \sqrt{3} < 2;\]

\[2 < \sqrt{5} < 3;\]

\[2 < \sqrt{8} < 3;\]

\[3 < \sqrt{10} < 4;\]

\[4 < \sqrt{20} < 5;\]

\[7 < \sqrt{50} < 8;\]

\[8 < \sqrt{75} < 9.\]