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Zhejiang senior high school entrance examination mathematics simulation volume
Solution: As can be seen from Figure ①, b=0,

Y=ax2+bx+a2+b is: y=ax2+a2,

∵ open, ∴ a > 0,

∵ intersects the Y axis on the negative semi-axis, that is, -3 < A2.

∴ does not meet the meaning of the problem;

As can be seen from Figure ②, b=0,

Y=ax2+bx+a2+b is: y=ax2+a2,

∵ opening down, ∴ a < 0,

∫ and the y axis intersects with the positive half axis, that is, 2 < A2 < 3,

∴-root No.3 < a

As can be seen from Figure ③:

∵ opening down, ∴ a < 0,

∵ Symmetry axis is on the right side of Y axis, ∴a and B have different symbols, that is, B > 0.

∫ The image intersects the positive semi-axis of the Y axis, ∴ A2+B > 0,

When x=- 1, y=0, a-b+a2+b = 0, a+a2=0,

∴a=- 1.

According to fig. 4, the opening is upward, ∴ A > 0,

∵ Symmetry axis is on the left side of Y axis, ∴a and B have the same sign, that is, B > 0.

The image intersects the Y axis on the negative semi-axis ∴a2+b=0,

Without such a and b,

∴ does not meet this question.

So choose a.

Very speechless, ..........................................! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !