ГДЗ по алгебре 9 класс Макарычев ФГОС Задание 86

\[\boxed{\text{87.\ }\text{ОК\ ГДЗ\ -\ домашка\ на\ 5}}\]

\[\textbf{а)}\ \frac{2a + 5b}{5a + 2b} = 1\]

\[2a + 5b = 5a + 2b\]

\[2a - 5a = 2b - 5b\]

\[- 3a = - 3b\]

\[\frac{a}{b} = 1.\]

\[\textbf{б)}\ \frac{a + 2b}{b + 2a} = - 3\]

\[a + 2b = - 3 \cdot (b + 2a)\]

\[a + 2b = - 3b - 6a\]

\[a + 6a = - 3b - 2b\]

\[7a = - 5b\]

\[\frac{a}{b} = - \frac{5}{7}.\]

\[\textbf{в)}\ \frac{99a + 8b}{4b - 100a} = 2\]

\[99a + 8b = 2 \cdot (4b - 100a)\]

\[99a + 8b = 8b - 200a\]

\[299a = 0b\]

\[\frac{a}{b} = 0.\ \]