maximize 101 + 122 +123
subject to
1 + 22 + 23 + 4= 20
21 + 2 + 23+5= 20
21 + 22 + 3 +6= 20
1, … , 6 ≥ 0
This is my first step for simplex tableau
x1 x2 x3 x4 x5 x6
0 4 1 2 2 1 0 0 20 20
x5 0 5 2 1 2 0 1 0 20 10
0 6 2 2 1 0 0 1 20 10
10 12 12 0 0 0 0
Now which variable should be entering variable?
What confuses me is since we have two 12 on cj-zj column, I suppose we should choose x2 or x3 as entering variable, but simplex calculator proceeds with x1 as entering variable.