Question

3. Найдите значение выражения​

Answer 1

Ответ:

$\frac{ {x}^{2} - {y}^{2} }{5 {x}^{2} } \div \frac{ {x}^{2} - 2xy + {y}^{2} }{25x} = \\ = \frac{(x - y)(x + y)}{5 {x}^{2} } \times \frac{25x}{(x - y) {}^{2} } = \\ = \frac{5(x + y)}{x(x - y) } \\ \\ x = 2 \\ y = 1 \\ \\ \frac{5(2 + 1)}{2(2 - 1)} = \frac{5 \times 3}{2} = 7.5$