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МатематикаРешебник по алгебре 8 класс Мерзляк ФГОС Задание 357
Задание 357
\[\boxed{\text{357\ (357).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
\[f(x) =\]
\[= \left\{ \begin{matrix} 4,\ \ если\ x \leq - 2\ \ \ \ \ \ \ \ \ \ \ \\ x^{2},\ \ если - 2 < x < 1 \\ 2x - 1,\ \ если\ x \geq 1\ \ \ \ \\ \end{matrix} \right.\ \]
\[1)\ f( - 3) = 4\]
\[f( - 2) = 4\]
\[f( - 1) = x^{2} = ( - 1)^{2} = 1\]
\[f(1) = 2x - 1 = 2 \cdot 1 - 1 = 1\]
\[f(3) = 2x - 1 = 2 \cdot 3 - 1 = 5\]
\[f(0,5) = x^{2} = {0,5}^{2} = 0,25\]
\[2)\ f(x) = x^{2}\]
| \[x\] | \[1\] | \[2\] | \[- 1\] | \[- 2\] |
|---|---|---|---|---|
| \[y\] | \[1\] | \[4\] | \[1\] | \[4\] |
\[f(x) = 2x - 1\]
| \[x\] | \[1\] | \[2\] |
|---|---|---|
| \[y\] | \[1\] | \[3\] |
\[\boxed{\text{357.}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
\[1)\ x^{2} = x - 1\]
\[y = x^{2}\]
| \[x\] | \[1\] | \[2\] | \[3\] | \[- 1\] | \[- 2\] |
|---|---|---|---|---|---|
| \[y\] | \[1\] | \[4\] | \[9\] | \[1\] | \[4\] |
\[y = x - 1\]
| \[x\] | \[0\] | \[1\] |
|---|---|---|
| \[y\] | \[- 1\] | \[0\] |
\[Ответ:нет\ корней.\]
\[2)\ x^{2} - 2x - 3 = 0\]
\[x^{2} = 2x + 3\]
\[y = x^{2}\]
| \[x\] | \[1\] | \[2\] | \[3\] | \[- 1\] | \[- 2\] |
|---|---|---|---|---|---|
| \[y\] | \[1\] | \[4\] | \[9\] | \[1\] | \[4\] |
\[y = 2x + 3\]
| \[x\] | \[1\] | \[- 1\] | \[3\] |
|---|---|---|---|
| \[y\] | \[5\] | \[1\] | \[9\] |
\[Ответ:\ x = - 1;x = 3.\]
\[3)\ x^{2} = \frac{8}{x}\]
\[y = x^{2}\]
| \[x\] | \[1\] | \[2\] | \[- 1\] | \[- 2\] |
|---|---|---|---|---|
| \[y\] | \[1\] | \[4\] | \[1\] | \[4\] |
\[y = \frac{8}{x}\]
| \[x\] | \[2\] | \[4\] | \[8\] | \[- 2\] | \[- 4\] | \[- 8\] |
|---|---|---|---|---|---|---|
| \[y\] | \[4\] | \[2\] | \[1\] | \[- 4\] | \[- 2\] | \[- 1\] |
\[Ответ:x = 2.\]
