Suppose I have the tableau below for a maximization problem. For the tableau to be optimal what are values for c1, c2, and b?

z x1 x2 x3 x4 x5 x6 RHS
1 c1 c2 0 0 0 0 10
0 4 a1 1 0 a2 0 b
0 -1 -5 0 1 -1 0 2
0 a3 -3 0 0 -4 1 3