Решебник по алгебре 9 класс Макарычев Задание 851

\[\boxed{\text{851\ (851).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]

\[2 \cdot P_{2} = 4;\]

\[2 \cdot P_{2} = 4;\]

\[P_{3} = 6;\]

\[4 + 4 + 6 = 14\ чисел.\]

\[P_{3} = 6;\]

\[2 \cdot P_{2} = 4;\]

\[P_{3} = 6;\]

\[6 + 4 + 6 = 16\ чисел.\ \]

\[\boxed{\text{851.}\text{\ }\text{ОК\ ГДЗ\ -\ домашка\ на\ 5}}\]

\[\left\{ \begin{matrix} (x + y)(8 - x) = 10 \\ (x + y)(y + 5) = 20 \\ \end{matrix} \right.\ \Longrightarrow\]

\[x^{2} - 19x + 78 = 0\]

\[D = 361 - 312 = 49\]

\[x_{1} = \frac{19 + 7}{2} = 13,\ \ \]

\[x_{2} = \frac{19 - 7}{2} = 6,\]

\[1)\ x_{1} = 13,\ \ y_{1} = - 15,\]

\[2)\ x_{2} = 6,\ \ y_{2} = - 1.\]

\[Ответ:(13;\ - 15);\ \ (6;\ - 1).\]