Question

Помогите решить номер 4

Answer 1

$\frac{4 - 3y}{y + 4} \div ( \frac{4 - y}{y + 4} + \frac{y}{y - 4} ) = \frac{4 - 3y}{y + 4} \div \frac{(4 - y)(y - 4) + y(y + 4)}{(y - 4)(y + 4)} = \frac{4 - 3y}{y + 4} \div \frac{4y - 16 - {y}^{2} + 4y + {y }^{2} + 4y}{(y - 4)(y + 4)} = \frac{4 - 3y}{y + 4} \div \frac{12y - 16}{(y - 4)(y + 4)} = \frac{(4 - 3y)}{(y + 4)} \times \frac{(y - 4)(y + 4)}{ - 4(4 - 3y)} = \frac{y - 4}{ - 4} = \frac{4 - y}{4}$