Решебник по алгебре 8 класс Мерзляк Задание 855

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\[1)\ x + \frac{a}{b} = 1\ \]

\[\ x = 1 - \frac{a}{b};\]

\[2)\ \frac{1}{x} + \frac{1}{a} = b\ \]

\[\frac{1}{x} = b - \frac{1}{a}\]

\[\frac{1}{x} = \ \frac{ab - 1}{a}\]

\[\ x = \frac{a}{ab - 1}\]

\[3)\ \frac{a}{b} + \frac{x}{4} = \frac{b}{a}\]

\[\text{\ \ }\frac{x}{4} = \frac{b}{a} - \frac{a}{b}\]

\[\frac{x}{4} = \frac{b^{2} - a^{2}}{\text{ab}}\]

\[\ x = \frac{4 \cdot (b^{2} - a^{2})}{\text{ab}}\]