a+b+c=6,2a-b+c=3,
把c看成常数,解得a=(9-2c)/3,b=(9-c)/3.
由b≥c≥0,即(9-c)/3≥c≥0,解得9/4≥c≥0,
a=(9-2c)/3随c增大而减小,在9/4≥c≥0范围内,
c=0时,a最大,amax=3,
c=9/4时,a最小,amin=3/2.
a+b+c=6,2a-b+c=3,
把c看成常数,解得a=(9-2c)/3,b=(9-c)/3.
由b≥c≥0,即(9-c)/3≥c≥0,解得9/4≥c≥0,
a=(9-2c)/3随c增大而减小,在9/4≥c≥0范围内,
c=0时,a最大,amax=3,
c=9/4时,a最小,amin=3/2.