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$\frac{ {y}^{2} - 6y + 9 }{ {y}^{2} - 9 } \div \frac{10y - 30}{ {y}^{2} + 3y }$

$\frac{(x - 3)^{2} }{(x - 3)(x + 3)} \times \frac{ x(x + 3)}{10x - 30}$

$\frac{(x - 3)}{(x + 3)} \times \frac{x(x + 3)}{10(x - 3)}$

Сократим на х+3:

$x - 3 \times \frac{x}{10(x - 3)}$

Сократим х-3:

$\frac{x}{10}$

Ответ:х/10

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