Consider the model given in Prob. 5.2-2. Let x6 and x7 be the slack variables for the first and second constraints, respectively. You are given the information that x2 is the entering basic variable and x7 is the leaving basic variable for the first iteration of the simplex method and then x4 is the entering basic variable and x6 is the leaving basic variable for the second (final) iteration. Use the procedure presented in Sec. 5.4 for updating B–1 from one iteration to the next to find B–1 after the first iteration and then after the second iteration.