在可行域3x1+2x2+6x3≥8
4x1+6x2+3x3≥10
x1,x2,x3≥0中,由边界得
x1=12/5-2x2,
x3=(10x2+2)/15,
所以目标函数z=500x1+400x2+600x3
=500(12/5-2x2)+400x2+600(10x2+2)/15
=1200-1000x2+400x2+400x2+80
=1280-200x2,
由x1,x2,x3≥0得0<=x2<=6/5,
所以1040<=z<=1280.
所以z的最小值是1040,最大值是1280.
可以吗?