Question

Помогите пожалуйста

Answer 1

Ответ:

$\frac{16 - 9 {y}^{2} }{4 {y}^{2} + 20y + 25} \div \frac{4 - 3y}{6y + 15} = \\ = \frac{ {4}^{2} - {(3y)}^{2} }{ {(2y)}^{2} + 2 \times 2y \times 5 + {5}^{2} } \times \frac{6y + 15}{4 - 3y} = \\ = \frac{(4- 3y)(4 + 3y)}{(2y + 5) {}^{2} } \times \frac{3(2y + 5)}{4 - 3y} = \\ = \frac{3(4 + 3y)}{2y + 5} \\ \\ \\ y = 2 \\ \\ \frac{3(4 + 6)}{4 + 5} = \frac{3 \times 10}{9} = \frac{10}{3} = 3 \frac{1}{3}$