已知：关于x的一元二次方程的一个根为，且二次函数的对称轴是直

已知：关于x的一元二次方程的一个根为，且二次函数的对称轴是直线，则抛物线的顶点坐标为 ( )

A. (2，3) B. (2，1) C. D. (3，2)

答案

解析:略

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已知：关于x的一元二次方程的一个根为，且二次函数的对称轴是直

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