Question

Помогите срочноооо!!

Answer 1

$(7 - \frac{m}{u} ) \div (7 + \frac{m}{u} ) = \\ = \frac{7u - m}{u} \div \frac{7u + m}{u} = \\ = \frac{7u - m}{u} \times \frac{u}{7u + m} = \\ = \frac{7u - m}{7u + m}$

ответ:

$\frac{7u - m}{7u + m}$