郭敦顒回答:maxz=2x1+x2+x3st:4x1+2x2+2x3≥4 (1)2x1+4x2≤20 (2)4x1+8x2+2x3≤1 (3)(3)-(2)得2x3≤-39,x3≤-19.54x1+2x2+2x3=4,4x1+8x2+2x3=1时,6x2=-3,x2=-0.5代入(2)得,2x1≤18,x1≤9将x1=9,x2=-0.5,x3=-19.5代入目标值得,maxz=2x1+ x2+ x3=18-0.5-19.5=-2,maxz=-2。