Решебник по математике 5 класс Мерзляк ФГОС Задание 1028

 

\[\boxed{\mathbf{1028\ (1028)}.\ Еуроки\ - \ ДЗ\ без\ мороки}\]

\[1)\ 43,4\ :3,5 = 12,4\ \left( \frac{км}{ч} \right) -\]

\[скорость\ по\ течению.\]

\[2)\ 39,6\ :4,5 = 8,8\ \left( \frac{км}{ч} \right) -\]

\[скорость\ против\ течения.\]

\[3)\ (12,4 - 8,8)\ :2 = 3,6\ :2 =\]

\[= 1,8\ \left( \frac{км}{ч} \right) - скорость\ \]

\[течения.\]

\[4)\ 12,4 - 1,8 = 10,6\ \left( \frac{км}{ч} \right) -\]

\[собственная\ скорость.\]

\[Ответ:1,8\ \frac{км}{ч};\ \ 10,6\ \frac{км}{ч}.\]

\[\boxed{\mathbf{1028}\mathbf{.}\mathbf{\ }}\]

\[1)\ \left( x - \frac{8}{9} \right) + \frac{3}{8} = \frac{19}{36}\text{\ \ \ \ \ }\]

\[x - \frac{8}{9} = \frac{19^{\backslash 2}}{36} - \frac{3^{\backslash 9}}{8}\text{\ \ \ \ \ }\]

\[x - \frac{8}{9} = \frac{38 - 27}{72}\]

\[x - \frac{8}{9} = \frac{11}{72}\text{\ \ \ \ }\]

\[\ x = \frac{11}{72} + \frac{8^{\backslash 8}}{9} = \frac{11 + 64}{72} = \frac{75}{72}\]

\[x = 1\frac{3}{72} = 1\frac{1}{24}\]

\[Ответ:1\frac{1}{24}.\]

\[2)\ 3\frac{5}{36} - \left( 1\frac{4}{9} - x \right) = \frac{17}{18}\text{\ \ \ \ \ }\]

\[1\frac{4}{9} - x = 3\frac{5}{36} - 1\frac{17^{\backslash 2}}{18}\]

\[1\frac{4}{9} - x = 3\frac{5}{36} - 1\frac{34}{36}\text{\ \ \ \ }\]

\[1\frac{4}{9} - x = 2\frac{41}{36} - 1\frac{34}{36}\]

\[1\frac{4}{9} - x = 1\frac{7}{36}\text{\ \ \ }\]

\[x = 1\frac{4^{\backslash 4}}{9} - 1\frac{7}{36} = 1\frac{16}{36} - 1\frac{7}{36}\]

\[x = \frac{9}{36} = \frac{1}{4}\]

\[Ответ:\ \frac{1}{4}.\]