I'm new to the dual problem.
As you see, here gives one primal problem.
I'm confusing about the constraint $3\leq x_3 \leq 4$, in the textbook I can not find the similar one.
Could anybody teach me how to deal with this kind of constraint? Just a hint is okay. Thank you very much.
$\min \quad x_1+2x_2+3x_3$
$\textrm{s.t.}\quad -x_1+3x_2\quad = 5$
$\quad \quad ~2x_1 - x_2 +3x_3 \geq 6$
$\quad \quad ~ \underline{3\leq x_3\leq4}$
$\quad \quad ~x_1\geq0$
$\quad \quad ~x_2\leq0$
Translate the last contraint $3\le x_3\le 4$ into two contraints such as
$x_3\ge 3$
and $x_3 \le 4$
So you will have five constraints to work with for this minimization problem.