要使x²+y²+Dx+Ey+F=0与x轴的两个交点分别位于原点两侧,则有(    )

A.D²+E²-4F＞0且F＞0                            B.D＜0,F＞0

C.D≠0,F≠0                                    D.F＜0

要使x²+y²+Dx+Ey+F=0与x轴的两个交点分别位于原点两侧,则有

1. A.
   D²+E²-4F＞0且F＞0
2. B.
   D＜0,F＞0
3. C.
   D≠0,F≠0
4. D.
   F＜0

A.D²＋E²－4F＞0且F＞0

B.D＜0,F＞0

C.D≠0,F≠0

D.F＜0