\[\boxed{\mathbf{П.\ 78}}\]
\[\textbf{а)}\ 0,46 \cdot \frac{3}{23} = 0,02 \cdot 3 = 0,06\]
\[\textbf{б)}\ 5,53\ :\frac{7}{9} = 5,53 \cdot \frac{9}{7} =\]
\[= 0,79 \cdot 9 = 7,11\]
\[\textbf{в)}\ \frac{5}{8} - 0,73 = 0,625 - 0,73 =\]
\[= - 0,105\]
\[\textbf{г)}\ 0,289\ :\frac{17}{18} = 0,289 \cdot \frac{18}{17} =\]
\[= 0,017 \cdot 18 = 0,306\]
\[\textbf{д)}\ 17,17\ :1\frac{5}{12} = 17,17\ :\frac{17}{12} =\]
\[= 17,17 \cdot \frac{12}{17} = 1,01 \cdot 12 = 12,12\]
\[\textbf{е)}\ 343,4\ :14\frac{3}{7} = 343,4\ :\frac{101}{7} =\]
\[= 343,4 \cdot \frac{7}{101} = 3,4 \cdot 7 = 23,8\]