因为最大值是8,所以(4ac-b^2)/(4a)=8....①代入A(-2,0),B(1,6)得4a-2b+c=0.....②a+b+c=6......③②-③得a=b-2......④将④代入③得c=8-2b....⑤将④⑤代入①得9b^2-16b=0b=0或16/9所以a=-2,b=0,c=8 或a=-2/9,b=16/9,c=40/9即f(x)=-2x^2+8或f(x)=(-2/9)x^2+(16/9)x+40/9