ГДЗ по алгебре 8 класс Макарычев ФГОС Задание 939

\[\boxed{\mathbf{939}\text{.\ }\text{еуроки}\text{-}\text{ответы}\text{\ }\text{на}\text{\ }\text{пятёрку}}\]

\[\textbf{а)}\ 7x - 2,4 < 0,4\]

\[7x < 0,4 + 2,4\]

\[7x < 2,8\]

\[x < 2,8\ \ :7\]

\[x < 0,4\]

\[( - \infty;0,4)\]

\[\textbf{б)}\ 1 - 5y > 3\]

\[- 5y > 3 - 1\]

\[- 5y > 2\]

\[y < - \frac{2}{5}\]

\[y < - 0,4\]

\[( - \infty;0,4)\]

\[\textbf{в)}\ 2x - 17 \geq - 27\]

\[2x \geq - 27 + 17\]

\[2x \geq - 10\]

\[x \geq - 5\]

\[\lbrack - 5;\ \infty)\]

\[\textbf{г)}\ 2 - 3a \leq 1\]

\[- 3a \leq 1 - 2\]

\[- 3a \leq - 1\]

\[a \geq \frac{1}{3}\]

\[\left\lbrack \frac{1}{3};\ + \infty \right)\]

\[\textbf{д)}\ 17 - x > 10 - 6x\]

\[- x + 6x > 10 - 17\]

\[5x > - 7\]

\[x > - \frac{7}{5}\]

\[x > - 1,4\]

\[( - 1,4;\ + \infty)\]

\[\textbf{е)}\ 30 + 5x \leq 18 - 7x\]

\[5x + 7x \leq 18 - 30\]

\[12x \leq - 12\]

\[x \leq - 1\]

\[( - \infty;\ - 1\rbrack\]

\[\textbf{ж)}\ 64 - 6y \geq 1 - y\]

\[- 6y + y \geq 1 - 64\]

\[- 5y \geq - 63\]

\[y \leq \frac{63}{5}\]

\[y \leq 12,6\]

\[( - \infty;12,6\rbrack\]

\[\textbf{з)}\ 8 + 5y \leq 21 + 6y\]

\[5y - 6y \leq 21 - 8\]

\[- y \leq 13\]

\[y \geq - 13\]

\[\lbrack - 13;\ + \infty)\]