As can be seen from the figure, when X= 1, Y=a+b+c=0.

Open the door, a>0,

Axis of symmetry X=-b/2a=- 1, so b=2a.

As can be seen from the figure. X=- 1 symmetry, one intersection point is 1 and the other is -3.

Y=a{X- 1][X+3]

When X=0, Y=-3a.

Y=0+0+c

So c=-3a.

a-2b+c=a-4a-3a=-6a

a》0

therefore

a-2 b+ c & lt； 0

① ③ Correct.