ГДЗ по алгебре 7 класс Макарычев Задание 234

\[\boxed{\text{234\ (234).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]

\[\textbf{а)}\ x^{2} + 4x + 3\]

\[(4)^{2} + 4 \cdot ( - 4) + 3 = 0\]

\[16 - 16 + 3 = 0\]

\[3 \neq 0 \Longrightarrow x = - 4\ (не\ корень)\]

\[(3)^{2} + 4 \cdot ( - 3) + 3 = 0\]

\[9 - 12 + 3 = 0\]

\[0 = 0 \Longrightarrow x = - 3\ (корень)\]

\[(1)^{2}\ + 4 \cdot ( - 1) + 3 = 0\]

\[1 - 4 + 3 = 0\]

\[0 = 0 \Longrightarrow x = - 1\ (корень)\]

\[(3)^{2} + 4 \cdot 3 + 3 = 0\]

\[9 + 12 + 3 = 0\]

\[24 \neq 0 \Longrightarrow x = 3 - не\ корень.\]

\[4^{2} + 4 \cdot 4 + 3 = 0\]

\[16 + 16 + 3 = 0\]

\[35 \neq 0 \Longrightarrow x = 4 - не\ корень.\]

\[\textbf{б)}\ x^{2} + x = 12\]

\[(4)^{2} - 4 = 12\]

\[16 - 4 = 12\]

\[12 = 12 \Longrightarrow x = - 4\ (корень)\]

\[(3)^{2} - 3 = 12\]

\[9 - 3 = 12\]

\[6 \neq 12 \Longrightarrow x = - 3\ (не\ корень)\]

\[(1)^{2} - 1 = 12\]

\[1 - 1 = 12\]

\[0 \neq 12 \Longrightarrow x = - 1\ (не\ корень)\]

\[3^{2} + 3 = 12\]

\[9 + 3 = 12\]

\[12 = 12 \Longrightarrow x = 3 - корень\]

\[4^{2} + 4 = 12\]

\[16 + 4 = 12\]

\[20 \neq 12\ \Longrightarrow x = 4 - не\ корень.\]