Решебник по алгебре 7 класс Мерзляк Задание 125

\[\boxed{\text{125\ (125).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]

\[1) - 9,6\ :12 = - \frac{96}{120} =\]

\[= - \frac{96\ :12}{120\ :12} = - \frac{8}{10} = - 0,8.\]

\[2) - 29\ :( - 5,8) = \frac{- 290}{- 58} = 5.\]

\[3)\ 4\ :( - 25) = - \frac{4}{25} = - 0,16.\]

\[4) - 0,8 + 5 = 4,2.\]

\[5)\ 4,2 + ( - 0,16) = 4,04.\ \]

\[Ответ:4,04.\]

\[1)\ 4 - 4,6 = - 0,6.\]

\[2) - 0,8 - 2,2 = - 3.\]

\[3) - 3,4 \cdot ( - 0,6) =\]

\[= 34 \cdot 6\ :100 = 2,04.\]

\[4)\ 12,4 \cdot ( - 3) = - 37,2.\]

\[5)\ 2,04 + ( - 37,2) = - 35,16.\ \]

\[Ответ:\ - 35,16.\]

\[1)\ 0,4 - \frac{3}{20} = \frac{8}{20} - \frac{3}{20} = \frac{5}{20} = \frac{1}{4}.\]

\[2)\ \frac{1}{4} \cdot 6\frac{2}{3} = \frac{1}{4} \cdot \frac{20}{3} = \frac{5}{3}.\]

\[3)\ 1,75\ :\left( - 7\frac{7}{8} \right) =\]

\[= 1\frac{3}{4}\ :\left( - 7\frac{7}{8} \right) = \frac{7}{4}\ :\left( - \frac{63}{8} \right) =\]

\[= - \frac{7 \cdot 8}{4 \cdot 63} = - \frac{2}{9}.\]

\[4)\frac{5}{3} - \left( - \frac{2}{9} \right) = \frac{5^{\backslash 3}}{3} + \frac{2}{9} =\]

\[= \frac{15}{9} + \frac{2}{9} = \frac{17}{9} = 1\frac{8}{9}\text{.\ \ }\]

\[Ответ:1\frac{8}{9}.\]

\[1)\ 6,3\ :\left( - \frac{9}{20} \right) = \frac{63}{10}\ :\left( - \frac{9}{20} \right) =\]

\[= - \frac{63 \cdot 20}{10 \cdot 9} = - \frac{7 \cdot 2}{1 \cdot 1} = - 14.\]

\[2) - 2,6\ :\left( - \frac{1}{20} \right) = \frac{26}{10}\ :\frac{1}{20} =\]

\[= \frac{13 \cdot 20}{5 \cdot 1} = \frac{13 \cdot 4}{1 \cdot 1} = 52.\]

\[3) - 14 + 52 = 38.\]

\[4)\ 38 \cdot \left( - \frac{4}{19} \right) = - \frac{38 \cdot 4}{19} =\]

\[= - \frac{2 \cdot 4}{1} = - 8.\ \]

\[5)\ - 0,6\ :( - 0,36) = \frac{6}{10}\ :\frac{9}{25} =\]

\[= \frac{6 \cdot 25}{10 \cdot 9} = \frac{2 \cdot 5}{2 \cdot 3} = \frac{10}{6} = \frac{5}{3}.\]

\[6) - 8 + \frac{5}{3} = - 8 + 1\frac{2}{3} =\]

\[= - 7\frac{3}{3} + 1\frac{2}{3} = - 6\frac{1}{3}\text{.\ }\]

\[Ответ:\ - 6\frac{1}{3}.\]