ГДЗ по алгебре 8 класс Макарычев ФГОС Задание 992

\[\boxed{\text{992.\ }\text{еуроки}\text{-}\text{ответы}\text{\ }\text{на}\text{\ }\text{пятёрку}}\]

\[\textbf{а)} - 6,5 < \frac{7x + 6}{2} \leq 20,5\ \ \ \ \ | \cdot 2\]

\[- 13 < 7x + 6 \leq 41\]

\[- 13 - 6 < 7x \leq 41 - 6\]

\[- 19 < 7x \leq 35\ \ \ |\ :7\]

\[- \frac{19}{7} < x \leq 5\]

\[\left( - \frac{19}{7};5 \right\rbrack;\ \ x = 1;2;5.\]

\[\textbf{б)} - 1 < \frac{4 - a}{3} \leq 5\ \ \ | \cdot 3\]

\[- 3 < 4 - a \leq 15\]

\[- 3 - 4 < - a \leq 15 - 4\]

\[- 7 < - a \leq 11\]

\[7 > a \geq - 11\]

\[- 11 \leq a < 7\]

\[\lbrack - 11;7);\ \ a = - 10;0;1\]

\[\textbf{в)} - 2 \leq \frac{3x - 1}{8} \leq 0\ \ \ | \cdot 8\]

\[- 16 \leq 3x - 1 \leq 0\]

\[- 16 + 1 \leq 3x \leq 0 + 1\]

\[- 15 \leq 3x \leq 1\ \ \ |\ :3\]

\[- 5 \leq x \leq \frac{1}{3}\]

\[\left\lbrack - 5;\frac{1}{3} \right\rbrack;\ \ x = - 5;\ - 1;0.\]

\[\textbf{г)} - 2,5 \leq \frac{1 - 3y}{2} \leq 1,5\ \ \ | \cdot 2\]

\[- 5 \leq 1 - 3y \leq 3\]

\[- 6 \leq - 3y \leq 2\ \ \ |\ :( - 3)\]

\[2 \geq y \geq - \frac{2}{3}\]

\[- \frac{2}{3} \leq y \leq 2\]

\[\left\lbrack - \frac{2}{3};2 \right\rbrack;\ \ y = 0;1;2.\]