\[\boxed{\text{237\ (237).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
Пояснение.
Решение.
\[\textbf{а)}\ y = x|x|\]
\[При\ x < 0:\]
\[y = - x \cdot x = - x^{2};\]
\[При\ x \geq 0:\]
\[y = x^{2}.\]
\[\textbf{б)}\ y = - \frac{x^{3}}{|x|};\ \ \ \ x \neq 0\]
\[x = 0 - выколотая\ точка.\]
\[При\ x < 0:\]
\[y = \frac{x^{3}}{x} = x^{2};\]
\[При\ x > 0:\]
\[y = - \frac{x^{3}}{x} = - x^{2}\text{.\ }\]