Apply one iteration of the Big-M method to the following LP. maximize subject to z1 + 212 .S 6 2x1 + 12 5 6 21 + 27 = 2 0 Use the Bland's rule to select the entering and leaving variable at each step. Step O Tableau and the first step's ratio test: z x1 x2 $1 a3 Irhs BV Ratio 1 .M-1 Z $1 O 0 The entering variable is The leaving variable is Step 1 Tableau: z x1 x2 Is1 a3 rhs BV Z The current basic feasible solution is: x1= X2 Z= Is this basic feasible solution optimal? (type yes or no)