解引进松弛变量x将问题化为标准形式 (I) min S=-x+ 2x2+ x3 2x1+x2-x3+x4=4 stx1+2x2=6 1,x2,x3,x4>0解 引进松弛变量 x4 , 将问题化为标准形式 (Ⅰ) min S = - x1+ 2x2+ x3 - 2x1+ x2 - x3+ x4 = 4 x1+ 2x2 = 6 x1 , x2 , x3 , x4≥0      s t