Question

Найдите произведение и сократите дробь:​

Answer 1

Ответ:

$\frac{a-2}{a+7}$

Объяснение:

$\frac{a^{2}- 8a +15 }{a^{2} - 49 } * \frac{a^{2}- 2a - 35 }{a^{2}- 25 }$

$\frac{(a - 2)(a - 5)}{(a-7)(a+7)}* \frac{(a+5)(a-7)}{(a - 5)(a+5)}\\\\\frac{(a - 2)(a - 5)(a+5)(a-7)}{(a-7)(a+7)(a - 5)(a+5)} \\\\\frac{a-2}{a+7}$

$1) a^{2} - 8a + 15 = 0\\D = 4 \\ x_{1} = 2\\x_{2} = 5\\(a-2)(a-5)\\\\2)a^{2} - 49 = a^{2} - 7^{2} \\(a-7)(a+7) \\\\3) a^{2} - 2a -35=0\\D= 64\\x_{1}= -5\\x_{2} = 7 \\(a+5)(a-7)\\\\4)a^{2} - 25 = a^{2} - 5^{2} \\(a-5)(a+5)$