Решебник по алгебре 7 класс Мерзляк Задание 439

\[\boxed{\text{439\ (439).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]

Пояснение.

Решение.

\[1)\ y^{2} - 6y = 0\]

\[y \cdot (y - 6) = 0\]

\[y = 0\ \ или\ \ y - 6 = 0\]

\[\text{\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ }y = 6\]

\[Ответ:y = 0;6.\]

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

\[x \cdot (x + 1) = 0\]

\[x = 0\ \ или\ \ x + 1 = 0\]

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

\[Ответ:x = 0;\ - 1.\]

\[3)\ 4m^{2} - 20m = 0\]

\[4m \cdot (m - 5) = 0\]

\[4m = 0\ \ или\ \ m - 5 = 0\]

\[\ \ \ m = 0\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ m = 5\]

\[Ответ:m = 0;\ 5.\]

\[4)\ 13x^{2} + x = 0\]

\[x \cdot (13x + 1) = 0\]

\[x = 0\ \ или\ \ 13x + 1 = 0\]

\[\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ x = - \frac{1}{13}\]

\[Ответ:x = 0;\ - \frac{1}{13}.\]

\[5)\ 9x^{2} - 6x = 0\]

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

\[3x = 0\ \ или\ \ 3x - 2 = 0\]

\[\ \ \ x = 0\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ x = \frac{2}{3}.\]

\[Ответ:x = 0;\frac{2}{3}.\]

\[6)\ 12x - 0,3x^{2} = 0\]

\[0,3x \cdot (40 - x) = 0\]

\[x = 0\ \ или\ 40 - x = 0\]

\[\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ x = 40.\]

\[Ответ:x = 0;40.\ \]