Решебник по алгебре 8 класс Мерзляк Задание 646

\[\boxed{\mathbf{646\ (646).\ }Еуроки\ - \ ДЗ\ без\ мороки}\]

\[x^{2} + 5x - 1 + \ *\ = 0\]

\[Пусть\ y = \ *\ .\]

\[1)\ Если\ x = 0\ \ \ и\ \ x = - 7,\ \ \ \]

\[запишем:\ \]

\[x(x + 7) = 0\]

\[x^{2} + 7x = 0\ \ \ \ \ \ и\ \ \ \ \ \ \]

\[x^{2} + 5x - 1 + \ *\ = 0\]

\[\left( x^{2} + 5x - 1 \right) + \underset{y}{\overset{2x + 1}{︸}} = 0\]

\[y = 2x + 1.\]

\[2)\ Если\ x = - 4\ \ \ и\ \ x = 4,\ \ \ \]

\[запишем:\]

\[(x + 4)(x - 4) = 0\]

\[x^{2} - 16 = 0\ \ \ \ \ и\ \ \ \ \ \ \]

\[x^{2} + 5x - 1 + \ * = 0\]

\[\left( x^{2} + 5x - 1 \right)\underset{y}{\overset{- 5x - 15}{︸}} = 0\]

\[y = - 5x - 15.\]