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一、利用二次函数图象直接判断参数的符号例1（2011年重庆，有改编）已知抛物线y=ax2＋bx=c（a≠0）在平面直角坐标系中的位置如图1所示．
观察图象巧判断
【摘 要】
：
一、利用二次函数图象直接判断参数的符号例1（2011年重庆，有改编）已知抛物线y=ax2＋bx=c（a≠0）在平面直角坐标系中的位置如图1所示．
【机 构】
：
江西
【出 处】
：
中学生数理化：初中版．中考版
【发表日期】
：
2004年期
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