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Пояснение.
Решение.
\[\textbf{а)}\ \frac{c^{\backslash b + c}}{b - c} + \frac{b^{2} - 3bc}{b^{2} - c^{2}} =\]
\[= \frac{cb + c^{2} + b^{2} - 3bc}{b^{2} - c^{2}} =\]
\[= \frac{c^{2} + b^{2} - 2bc}{b^{2} - c^{2}} =\]
\[\textbf{б)}\ \frac{a + 3}{a^{2} - 1} - \frac{1}{a^{2} + a} =\]
\[= \frac{a + 3^{\backslash a}}{(a - 1) \cdot (a + 1)} - \frac{1^{\backslash a - 1}}{a \cdot (a + 1)} =\]
\[= \ \frac{a^{2} + 3a - a + 1}{a \cdot (a + 1) \cdot (a - 1)} =\]
\[= \frac{a^{2} + 2a + 1}{a \cdot (a + 1) \cdot (a - 1)} =\]
\[= \frac{a + 1}{a \cdot (a - 1)}\]