#1. Combining the columns 1 and 3  and scaling columns 2, 4  gives x1    x2   -1 1    -4   -4 = x1 -2 -12  -8 = -x3 0     0   -2  ->max The tableau is still not standard. It can be made standard using a pivot step. Or we can observe that the first row says x2=1. So the tableau becomes x1  -1 -2   4 = -x3 0   -2  ->max which is standard. It is optimal, so max = 2 at x1= 0, x3 = 4 and (see above) x2 = 1. All optimal solutions are given by x2 = 1,  x1 >= 0, x3= 4+2x1. #2. Multiply x7 and x8 rows by -1 to obtain the standard tableau x1  x2  x3 x4  x5  -1       2         -5          -2  = -x6      -e          0          -1  = -x7       0         -4          -2  = -x8       0          1              ->max where e =1/10^(-100) > 0. The x4 column is bad but the tableau is not feasible. The row problem is infeasible or unbounded by the theorem on 4 alternatives. Now instead of simplex method, we can restrict ourselves  to x4=x2 which gives the standard tableau x1  x2  x3  x5  -1       -3           -2  = -x6       -e           -1  = -x7       -4           -2  = -x8        1                          ->max with x2-column bad. The tableau is still not feasible. But setting x1=x3=x5=0 and sending x2 to infinity, we obtain feasible solutions (the entries in x2 column overcome the the entries in the last column) with arbitrary large values for f. Answer: max = infinity (the LP is unbounded). #3. The easiest way to solve #3 is graphical method. We have 0 <= x1 <= 1, 0 <= x2 <= 1, x1+x2 <= 1.5 for the feasible region. x2 1 ________  x1=0.5, x2 = 1 (optimal solution). 3x1+4x2 = 5.5 = max.                 \                    \                       \                          \                           |                           |                           | 0 --------------------- --1---------------> x1 Do not forget x3=1-x1 = 0.5, x4= 1 -x2 = 0,x5=3-2x1-2x2=0. #4. There are two equilibria in pure strategies: rows 2 and 5, column 6 with the value of game 8. Every equilibrium in mixed strategies is a mixture of these two. #5. We have the following dominations: c1 > c2; r3 > r2 > r1,; r3 > r4. Then  (after crossing out c2, r2, r1,r4) x1>c5,c6; c4 > c7 > c4. So we are reduced to 2 by 2 matrix game       c1  c4 or c7 r3     2         0 r5     0         4 He (the row player) has only one optimal strategy, p= (2r3+r5)/3.   Her optimal strategy is (2c1+c4)/3 where c4 can be replaced by ay mixture of c4 and c7 to obtain every optimal strategy. The value of game is 4/3.       c1   c4 (2c1+c4)/3 r3     2         0 4/3 r5     0         4 4/3 p 4/3 4/3 4/3*^