Решебник по алгебре 8 класс Мерзляк Задание 69

\[\boxed{\text{69\ (69).\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]

Пояснение.

Решение.

\[1)\ \frac{7k}{18p} - \frac{4k}{18p} = \frac{7k - 4k}{18p} = \frac{3k}{18p}\]

\[= = \frac{k}{6p}\]

\[2)\ \frac{a - b}{2b} - \frac{a}{2b} = \frac{a - b - a}{2b} =\]

\[= \frac{- b}{2b} = - \frac{1}{2}\]

\[3)\ - \frac{a - 12b}{27a} + \frac{a + 15b}{27a} =\]

\[\text{=}\frac{a + 15b - a + 12b}{27a} = \frac{27b}{27a} = \frac{b}{a}\]

\[4)\ \frac{x - 7y}{\text{xy}} - \frac{x - 4y}{\text{xy}} =\]

\[= \frac{x - 7y - x + 4y}{\text{xy}} = \frac{- 3y}{\text{xy}} = - \frac{3}{x}\]

\[5)\ \frac{10a + 6b}{11a^{3}} - \frac{6b - a}{11a^{3}} =\]

\[= \frac{10a + 6b - 6b + a}{11a^{3}} = \frac{11a}{11a^{3}} =\]

\[= \frac{1}{a^{2}}\]

\[6)\ \frac{x^{2} - xy}{x^{2}y} + \frac{2xy - 3x^{2}}{x^{2}y} =\]

\[= \frac{x^{2} - xy + 2xy - 3x^{2}}{x^{2}y} =\]

\[= \frac{- 2x^{2} + xy}{x^{2}y} =\]

\[= \frac{x(y - 2x)}{x^{2}y} = \frac{y - 2x}{\text{xy}}\]