5.25 The graph (schematic diagram) of the function $y=a x^{2}+b x+c(a>0, b<0, c<0)$ is
(A)
(B)
(C)
(D)
(Jilin Province Seven Cities and Prefectures Junior High School Mathematics Competition, 1984)
[Solution] From the given, we know that $\Delta=b^{2}-4 a c>0$, so the equation has two distinct real roots, thus we can rule out (A), (B).
The axis of symmetry of the parabola is given by $x=-\frac{b}{2 a}>0$, so we can rule out (C). Therefore, the answer is (D).