max z= 2X1 +3x2 +X3 S t +3x2+x3<1 3X2 583 0 min Z =15 2x1+3max z= 2x1 +3x2 +x3 s.t. x1 +3x2 +x3 15 2x1 +3x2 -x3 18 x1 -x2 +x3 3 x1, x2, x3 0 min z’= -2x1 -3x2 -x3 st x1 +3x2 +x3 +x4 =15 2x1 +3x2 -x3 +x5 =18 x1 -x2 +x3 +x6 =3 x1, x2, x3, x4, x5, x6 0