挑战习题
1/5单选题
难度:

1.如图,已知抛物线y= x2 - x-3与x轴的交点为A、D(A在D的右侧),与y轴的交点为C. 若点M在抛物线对称轴上,使得MD+MC的值最小时,点M的坐标为(    )
A (1,
B (1,-
C,1)
D (1,-
提示1:
IOaJvuWIsOeCuUTlhbPkuo7mipvniannur/lr7nnp7DovbTnmoTlr7nnp7DngrlB77yM6L+e57uTQUPvvIzmoLnmja7lvoXlrprns7vmlbDms5Xlj6/lvpfnm7Tnur9BQ+eahOino+aekOW8j++8jOS7pHg9Me+8jOaxguW+l+aKm+eJqee6v+WvueensOi9tOS4juebtOe6v0FD55qE6Kej5p6Q5byP55qE5Lqk54K55Z2Q5qCH77yM5Y2z5Li65omA5rGC54K5TeeahOWdkOaghw==
正确答案:Qg==
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