\[\boxed{\text{1192.\ }\text{еуроки}\text{-}\text{ответы}\text{\ }\text{на}\text{\ }\text{пятёрку}}\]
\[\textbf{а)}\ А\ (1,5;8);\ \ y = \frac{k}{x}\]
\[x = 1,5;\ \ y = 8\]
\[8 = \frac{k}{1,5}\ \ \ \ \ | \cdot 1,5\]
\[k = 12.\]
\[\textbf{б)}\ В\ (0,04;\ - 25);\ \ y = \frac{k}{x}\]
\[x = 0,04;\ \ \ y = - 25\]
\[- 25 = \frac{k}{0,04}\ \ \ \ \ | \cdot 0,04\]
\[k = - 1.\]