Решебник по алгебре 9 класс Мерзляк Задание 346

\[\boxed{\text{346\ (346).\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]

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

\[x_{0} = \frac{- 2}{2} = - 1;\]

\[y_{0} = 1 - 2 - 8 = - 9.\]

\[\text{Ox}:\ \ \]

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

\[x_{1} + x_{2} = - 2,\ \ x_{1} = - 4,\ \ \]

\[( - 4;0)\]

\[x_{1}x_{2} = - 8,\ \ x_{2} = 2,\ \ \]

\[(2;0).\]

\[Oy:\ \ \]

\[y = - 8;\ \ x = 0,\ \ (0; - 8)\]

\[y( - 3) = 9 - 6 - 8 = - 5.\]

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

\[x_{0} = \frac{2}{2} = 1;\]

\[y_{0} = 1 - 2 = - 1.\]

\[Ox:\]

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

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

\[x = 0,\ \ x = 2,\ \ \]

\[(0;0),\ \ (2;0).\]

\[Oy:\ \ \]

\[y = 0;\ (0;0).\]

\[y( - 1) = 1 + 2 = 3.\]

\[3)\ y = - x^{2} + 4x - 5\]

\[x_{0} = \frac{- 4}{- 2} = 2;\ \]

\[y_{0} = - 4 + 8 - 5 = - 1.\]

\[Ox:\ \ \ \]

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

\[D = 16 - 20 < 0 - \ точек\ нет.\]

\[Oy:\ \ \ \]

\[y = - 5;\ \ \ (0;\ - 5).\]

\[y(1) = - 1 + 4 - 5 = - 2.\]

\[4)\ y = 2x^{2} - 2x - 4\]

\[x_{0} = \frac{2}{4} = 0,5\]

\[y_{0} = 0,5 - 1 - 4 = - 4,5\]

\[\text{Ox}:\ \ 2x^{2} - 2x - 4 = 0\ \ |\ :2\]

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

\[x_{1} + x_{2} = 1,\ \ x_{1}x_{2} = - 2,\ \ \]

\[x_{1} = 2,\ \ x_{2} = - 1.\]

\[(2;0),\ \ ( - 1;0).\]

\[\text{Oy}:\ \ \]

\[\ y = - 4,\ \ (0; - 4).\]