Решебник по алгебре 9 класс Макарычев Задание 229

 

\[\boxed{\text{229}\text{\ (229)}\text{.}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]

\[Подставим\ данные\ в\ задании\ \]

\[числа\ вместо\ соответствующих\]

\[значений\ аргумента\ (x)\ и\ \]

\[функции\ (y).\]

\[y = ax^{2}\]

\[\textbf{а)}\ (5;\ - 7):\ \ \ \]

\[- 7 = a \cdot 5^{2}\]

\[- 7 = 25a\]

\[a = - \frac{7}{25}\]

\[Ответ:при\ a = - \frac{7}{25}.\]

\[\textbf{б)}\ \left( - \sqrt{3};9 \right):\ \ \]

\[9 = a \cdot \left( - \sqrt{3} \right)^{2}\]

\[9 = 3a\]

\[a = 3\]

\[Ответ:при\ a = 3.\]

\[\textbf{в)}\ \left( - \frac{1}{2};\ - \frac{1}{2} \right):\ \ \]

\[- \frac{1}{2} = a \cdot \left( - \frac{1}{2} \right)^{2}\]

\[- \frac{1}{2} = a \cdot \frac{1}{4}\]

\[a = - \frac{1}{2}\ :\frac{1}{4}\]

\[a = - 2\]

\[Ответ:при\ a = - 2.\]

\[\textbf{г)}\ (100;10):\]

\[10 = a \cdot 100^{2}\]

\[10 = 10\ 000a\]

\[a = \frac{10}{10000}\]

\[a = 0,001\]

\[Ответ:при\ a = 0,001.\]

\[\boxed{\text{229.}\text{\ }\text{ОК\ ГДЗ\ -\ домашка\ на\ 5}}\]

\[\textbf{а)}\ y^{7} - y^{6} + 8y = 8\]

\[y^{7} - y^{6} + 8y - 8 = 0\]

\[y^{6} \cdot (y - 1) + 8 \cdot (y - 1) = 0\]

\[\left( y^{6} + 8 \right)(y - 1) = 0\]

\[y - 1 = 0\ \ \ \ \ или\ \ \ \ y^{6} + 8 = 0\]

\[y_{1} = 1\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \]

\[\text{\ \ \ \ }y^{6} = - 8 \Longrightarrow корней\ нет.\]

\[Ответ:y = 1.\]

\[\textbf{б)}\ u^{7} - u^{6} = 64u - 64\]

\[u^{7} - u^{6} - 64u + 64 = 0\]

\[u^{6} \cdot (u - 1) - 64 \cdot (u - 1) = 0\]

\[(u - 1)\left( u^{6} - 64 \right) = 0\]

\[(u - 1)\left( \left( u^{3} \right)^{2} - 8^{2} \right) = 0\]

\[(u - 1)\left( u^{3} - 8 \right)\left( u^{3} + 8 \right) = 0\]

\[u - 1 = 0\ \ \ \ \ или\ \ \ u^{3} = 8\ \ \ или\ \ \]

\[\ u^{3} = - 8\]

\[u_{1} = 1\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ u_{2} = 2\ \ \ \ \ \ \ \ \ \]

\[\text{\ \ \ \ }u_{3} = - 2.\]

\[Ответ:u = 1;\ \ u = \pm 2.\]