2/5 + 7/8
________
9/10 - 3/4

Нужно решение))

[tex] \frac{ \frac{2}{5}+ \frac{7}{8} }{ \frac{9}{10}- \frac{3}{4} } = \frac{ \frac{16}{40}+ \frac{35}{40} }{ \frac{18}{20}- \frac{15}{20} } = \frac{ \frac{51}{40} }{ \frac{3}{20}} = \frac{51}{40} * \frac{20}{3} = \frac{17}{2} * \frac{1}{1} =8 \frac{1}{2} [/tex]