设(x-1)/2=(2-y)/3=(z-3)/4=kx-1=2k,x=2k+12-y=3k,y=2-3kz-3=4k,z=4k+3W=3(2k+1)+4(2-3k)+5(4k+3)=6k+3+8-12k+20k+15=6k+26因为x>=0,y>=0,z>=02k+1>=0,k>=-0.52-3k>=0,k<=2/34k+3>=0,k>=-3/4所以-0.5<=k<=2/3Wmin=6*(-0.5)+26=23Wmax=6*2/3+26=30