How can I turn this into canonical form and then use the two-phase simplex method to solve it?
$$max\quad -2x_1-x_2-x_3 \\ \text{subject to: }-x_1-x_3 \le -1 \\ -x_1+x_2 \le -2 \\ -x_2+x_3 \le -1 \\ x_1,x_2,x_3 \ge 0 $$
When I put it into the tableau with only slack variables there are no negative coefficients in the bottom room to find the column to pivot around
