20 10 Bazhong Mathematics Senior High School Entrance Examination
y=ax? +bx+c=a(x? +b/a x)+c=a(x+b/2a x)^2-b? /4a+c, because the opening of the quadratic function is downward, so A 0,b? > 4ac, so c < 0, vertex coordinates (-b/2a, 4ac-b? /4a)、4ac-b? /4a > 0, because x=- 1/3, so -b/2a=- 1/3, and a=3/2 b, so the correct ones are: 1, 2, 3, 5.