ГДЗ по алгебре 8 класс Макарычев ФГОС Задание 945

\[\boxed{\text{945.\ }\text{еуроки}\text{-}\text{ответы}\text{\ }\text{на}\text{\ }\text{пятёрку}}\]

\[\textbf{а)}\ a(a - 4) - a^{2} > 12 - 6a\]

\[a^{2} - 4a - a^{2} > 12 - 6a\]

\[- 4a + 6a > 12\]

\[2a > 12\]

\[a > 6 \Longrightarrow \ a \in (6;\ + \infty)\]

\[\textbf{б)}\ (2x - 1) \cdot 2x - 5x < 4x^{2} - x\]

\[4x^{2} - 2x - 5x < 4x^{2} - x\]

\[- 2x - 5x + x < 0\]

\[- 6x < 0\]

\[x > 0 \Longrightarrow \ \ x \in (0;\ + \infty)\]

\[\textbf{в)}\ 5y² - 5y(y + 4) \geq 100\]

\[5y^{2} - 5y^{2} - 20y \geq 100\]

\[- 20y \geq 100\]

\[y \leq - 5 \Longrightarrow \ \ y \in ( - \infty;\ - 5\rbrack\]

\[\textbf{г)}\ 6a(a - 1) - 2a(3a - 2) < 6\]

\[6a^{2} - 6a - 6a^{2} + 4a < 6\]

\[- 2a < 6\]

\[a > - 3 \Longrightarrow \ \ a \in ( - 3;\ + \infty).\]