Решебник по алгебре 7 класс Мерзляк ФГОС Задание 267

 

\[\boxed{\text{267\ (}\text{н}\text{).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]

\[1)\ 5x^{2}\]

\[при\ x = - 4:\]

\[5 \cdot ( - 4)^{2} = 5 \cdot 16 = 80.\]

\[2) - 4,8a^{4}b^{3}\text{\ \ }\]

\[если\ a = - 1;\ \ b = \frac{1}{2}:\]

\[- 4,8 \cdot ( - 1)^{4} \cdot \left( \frac{1}{2} \right)^{3} =\]

\[= - 4,8 \cdot \frac{1}{8} = - 0,6.\]

\[3)\ \frac{4}{9}m^{3}n^{2}p^{3}\]

\[если\ m = - 3;\ \ n = 5;\ \ p = - 1:\]

\[\frac{4}{9} \cdot ( - 3)^{3} \cdot 5^{2} \cdot ( - 1)^{3} =\]

\[= \frac{4}{9} \cdot 27 \cdot 25 = 12 \cdot 25 = 300.\]

\[\boxed{\text{267\ (}\text{с}\text{).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]

\[1)\ 5x^{2}\ \]

\[\ при\ x = - 4:\]

\[5 \cdot ( - 4)^{2} = 5 \cdot 16 = 80.\]

\[2) - 4,8a^{4}b^{3}\]

\[\ \ если\ a = - 1;\ b = \frac{1}{2}:\ \]

\[- 4,8 \cdot ( - 1)^{4} \cdot \left( \frac{1}{2} \right)^{3} =\]

\[= - 4,8 \cdot \frac{1}{8} = - 0,6.\]

\[3)\ 0,04c^{3}d^{5}\]

\[\ если\ c = - 10;\ \ d = 2:\]

\[0,04 \cdot ( - 10)^{3} \cdot 2^{5} =\]

\[= 0,04 \cdot 1000 \cdot 32 =\]

\[= - 40 \cdot 32 = - 1280.\]

\[4)\ \frac{4}{9}m^{3}n^{2}p^{3}\]

\[\ \ если\ m = - 3;\ \ n = 5;\ \ p = - 1:\]

\[\frac{4}{9} \cdot ( - 3)^{3} \cdot 5^{2} \cdot ( - 1)^{3} =\]

\[= \frac{4}{9} \cdot 27 \cdot 25 = 12 \cdot 25 = 300.\]

\[\boxed{\text{267.}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]

\[8 < 3^{n} < 85\]

\[3^{2} = 9 \Longrightarrow 8 < 9 < 85.\]

\[3^{3} = 27 \Longrightarrow \ 8 < 27 < 85.\]

\[3^{4} = 81 \Longrightarrow \ 8 < 81 < 85.\]

\[Ответ:n = 2;3;4.\ \]