Помогите пожалуйста.

$1) \frac{12ab}{4a} = 3y \\ \\ 2) \frac{3c(1 - c)}{9c {}^{2}(c - 1) } = \frac{ - ( c - 1)}{3c \times (c - 1)} = - \frac{1}{3c} \\ \\ 3) \frac{12x - 3x {}^{3} }{6x + 6} = \frac{3 \times (4x - x {}^{3}) }{3 \times (2x + 2)} = \frac{4x - x {}^{3} }{2x + 2} \\ \\ 4) \frac{m {}^{2} - 4 }{m {}^{2} + 4m + 4} = \frac{(m - 2) \times (m + 2)}{(m + 2) {}^{2} } = \frac{m - 2}{m + 2} \\ \\ 5) \frac{y - 3}{y {}^{2} - 6y + 9 } = \frac{y - 3}{(y - 3) {}^{2} } = \frac{1}{y - 3}$

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