\[\boxed{\text{681.}\text{\ }\text{еуроки}\text{-}\text{ответы}\text{\ }\text{на}\text{\ }\text{пятёрку}}\]
\[\textbf{а)}\ y - x^{2} = 0\]
\[y = x^{2}\]
\[\textbf{б)}\ y - x^{3} = 0\]
\[y = x^{3}\]
\[\textbf{в)}\ 0,5xy + 1,5 = 0\ \ \ \]
\[0,5xy = - 1,5\]
\[xy = - 3\]
\[y = - \frac{3}{x}\]
\[\textbf{г)}\ y + x^{3} = 0\]
\[y = - x^{3}\]