题目

26. –Look! How terrible his situation is! Could you help him?    --I’d like to help, but ____ I can’t. A. fortunately  B. luckily    C. unfortunately       D. gradually 答案：C如图，二次函数y=ax2+bx+c的图象与x轴交于B、C两点，与y轴交于点A（0，-3），∠ABC=45°，∠ACB=60°，求这个二次函数解析式．