ГДЗ по алгебре 8 класс Макарычев ФГОС Задание 842

\[\boxed{\text{842.\ }\text{еуроки}\text{-}\text{ответы}\text{\ }\text{на}\text{\ }\text{пятёрку}}\]

\[\textbf{а)}\ 3 \cdot (a + 1) + a < 4 \cdot (2 + a)\]

\[3a + 3 + a < 8 + 4a\]

\[4a + 3 < 8 + 4a\]

\[3 < 8\]

\[\textbf{б)}\ (7p - 1)(7p + 1) < 49p²\]

\[49p^{2} + 7p - 7p - 1 < 49p^{2}\]

\[49p^{2} - 1 < 49p²\]

\[- 1 < 0\]

\[\textbf{в)}\ (a - 2)^{2} > a(a - 4)\]

\[a^{2} - 4a + 4 > a^{2} - 4a\]

\[a^{2} + 4 > a^{2}\]

\[4 > 0\]

\[\textbf{г)}\ (2a + 3)(2a + 1) > 4a(a + 2)\]

\[4a^{2} + 2a + 6a + 3 > 4a^{2} + 8a\]

\[4a^{2} + 3 > 4a^{2}\]

\[3 > 0\]