\[\boxed{\text{1028.\ }\text{еуроки}\text{-}\text{ответы}\text{\ }\text{на}\text{\ }\text{пятёрку}}\]
\[12 \leq y \leq 16\]
\[\textbf{а)} - 12 \geq - y \geq - 16\]
\[- 16 \leq - y \leq - 12\]
\[- 16 \cdot 0,5 \leq - 0,5y \leq - 12 \cdot 0,5\]
\[- 8 \leq - 0,5y \leq - 6\]
\[\textbf{б)} - 16 \leq - y \leq - 12\]
\[- 32 \leq - 2y \leq - 24\]
\[42 - 32 \leq 42 - 2y \leq 42 - 24\]
\[10 \leq 42 - 2y \leq 18\]
\[\textbf{в)}\frac{1}{16} \leq \frac{1}{y} \leq \frac{1}{12}\]
\[2\frac{1}{16} \leq \frac{1}{y} + 2 \leq 2\frac{1}{12}\]