2/5 + 7/8________9/10 - 3/4Нужно решение))

[latex] 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} [/latex]