Помогите пожалуйста!!! Всё ((

=============== 1 ===============

$(2 \frac{1}{4} +3 \frac{2}{3} ):(8 \frac{1}{2} -1 \frac{2}{5} ) \cdot 1.2 = (\frac{9}{4} + \frac{11}{3} ):( \frac{17}{2} - \frac{7}{5} ) \cdot 1 \frac{2}{10} =\\\\ =(\frac{9 \cdot 3+11 \cdot4}{12} ):( \frac{17 \cdot 5-7\cdot2}{2} ) \cdot 1 \frac{1}{5} =\frac{71}{12} : \frac{71}{2} \cdot \frac{6}{5} =\frac{71}{12} \cdot \frac{2}{71} \cdot \frac{6}{5} = \frac{1}{5}$

=============== 2 ===============

$2 \frac{1}{3} x-2 \frac{3}{5} =1 \frac{2}{15} \\\\ \frac{7}{3} x-\frac{13}{5} = \frac{17}{15} \\\\ \frac{7}{3} x = \frac{17}{15}+\frac{13}{5} \\\\ \frac{7}{3} x = \frac{17+13 \cdot 3}{15} \\\\ \frac{7}{3} x = \frac{56}{15} | \cdot \frac{3}{7} \\\\ x = \frac{8}{5} \\\\ x = 1\frac{3}{5} \\\\$

=============== 3 ===============
$v= \frac{S}{t} \Rightarrow v= \frac{52 \frac{1}{2} }{ \frac{5}{6} } = \frac{105}{2} : \frac{5}{6} = \frac{105}{2} \cdot \frac{6}{5} = 21 \cdot 3 = 63$

Ответ: 63 км/ч