Решебник по алгебре 7 класс Мерзляк Задание 794

\[\boxed{\text{794\ (794).\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]

\[1)\ f(3) = 2 \cdot 3 - 1 = 5,\ \]

\[\text{\ f}( - 4) = 2 \cdot ( - 4) - 1 = - 9\]

\[f(0) = 0 - 1 = - 1,\ \]

\[\text{\ f}( - 0,5) = 2 \cdot ( - 0,5) - 1 = - 2\]

\[f(3,2) = 2 \cdot 3,2 - 1 = 5,4\]

\[2)\ f(x) = 7\ \]

\[\ 2x - 1 = 7\]

\[\ 2x = 8\ \]

\[x = 4.\]

\[f(x) = - 9\ \]

\[\ 2x - 1 = - 9\]

\[\ 2x = - 8\ \]

\[\ x = - 4.\]

\[f(x) = 0\ \ \]

\[2x - 1 = 0\]

\[2x = 1\]

\[x = \frac{1}{2}.\]

\[f(x) = - 2,4\ \]

\[2x - 1 = - 2,4\ \]

\[2x = - 1,4\ \ \]

\[x = - 0,7.\]

\[3)\ f(5) = 2 \cdot 5 - 1 = 9 \Longrightarrow\]

\[\Longrightarrow верно;\]

\[f(0,3) = 2 \cdot 0,3 - 1 = 0,6 - 1 =\]

\[= - 0,4 \Longrightarrow неверно;\]

\[f( - 3) = 2 \cdot ( - 3) - 1 = - 7 \Longrightarrow\]

\[\Longrightarrow верно.\]