ГДЗ по алгебре 7 класс Макарычев Задание 715

\[\boxed{\text{715\ (715).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]

Пояснение.

Решение.

\[\textbf{а)}\ ax - y + x - ay =\]

\[= (x - y)(a + 1)\]

\[(ax + x) - (ay + y) =\]

\[= (x - y)(a + 1)\]

\[x(a + 1) - y(a + 1) =\]

\[= (x - y)(a + 1)\]

\[(a + 1)(x - y) = (x - y)(a + 1)\]

\[(x - y)(a + 1) = (x - y)(a + 1)\]

\[Тождество\ верно.\]

\[\textbf{б)}\ ax - 2by + ay - 2bx =\]

\[= (a - 2b)(x + y)\]

\[(ax - 2bx) + (ay - 2by) =\]

\[= (a - 2b)(x + y)\]

\[x(a - 2b) + y(a - 2b) =\]

\[= (a - 2b)(x + y)\]

\[(a - 2b)(x + y) =\]

\[= (a - 2b)(x + y)\]

\[Тождество\ верно.\]