Solution
= Solution
{c}
There are two primal inequalities, so there are two nonnegative <dual variables>. The five primal <variables> yield five dual inequalities:
$$
\boxed{\begin{gathered}
\text{minimise }2y_1+y_2,\\
y_1+y_2\ge1,\qquad -y_1+y_2\ge-1,\\
-y_1+3y_2\ge-5,\qquad 3y_1+4y_2\ge12,\\
3y_1+y_2\ge6,\qquad y_1,y_2\ge0.
\end{gathered}}
$$
Each coefficient column of the primal <linear program> becomes one row of this <dual linear program>.