Question

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Answer 1

Ответ:

$1)\frac{a-3}{2a+4} *\frac{a^2-4}{a^3-27} =\frac{a-3}{2(a+2)} *\frac{(a+2)(a-2)}{(a-3)(a^2+3a+9)} =>\frac{a-2}{2(a^2+3a+9)}$    $2)\frac{c^2-1}{c^3+1} :\frac{c-1}{c^2-c+1} =\frac{(c+1)(c-1)}{(c+1)(c^2-c+1)} *\frac{c^2-c+1}{c-1 } => 1$

Answer 2

Объяснение:

$\\ \frac{a - 3}{2a + 4} \times \frac{a {}^{2} - 4 }{a {}^{3} - 27} = \frac{a - 3}{2 \times (a + 2)} \times \frac{(a - 2)(a + 2)}{(a - 3) \times ( a {}^{2} + 3a + 9) } = \frac{1}{2} \times \frac{a - 2}{a {}^{2} + 3a + 9} = \frac{a - 2}{2 \times (a {}^{2} + 3a + 9) } = \frac{a - 2}{2a {}^{2} + 6a + 18} \\ \\ \frac{c {}^{2} - 1 }{c {}^{3} + 1} \div \frac{c - 1}{c {}^{2} - c + 1} = \frac{(c - 1)(c + 1)}{(c + 1) \times (c {}^{2} - c + 1) } \times \frac{c {}^{2} - c + 1 }{c - 1} = \frac{c + 1}{(c + 1) \times (c {}^{2} - c + 1) } \times (c {}^{2} - c + 1) = \frac{1}{c {}^{2} - c + 1} \times (c {}^{2} - c + 1) = 1$