Ответ:

[tex]7\frac{1}{2}[/tex]

Пошаговое объяснение:

[tex]6\frac{3}{8}*1\frac{7}{17}-2\frac{3}{8}:1\frac{1}{4}+\frac{2}{5}=\frac{51}{8}*\frac{24}{17}-\frac{19}{8}:\frac{5}{4}+\frac{2}{5}=\\\\=\frac{3}{1}*\frac{3}{1}-\frac{19}{8}*\frac{4}{5}+\frac{2}{5}=9-\frac{19}{10}+\frac{2}{5}=9-\frac{19}{10}+\frac{4}{10}=\\\\=9-\frac{15}{10}=9-\frac{3}{2}=9-1\frac{1}{2}=7\frac{1}{2}[/tex]