已知二次函数y=-
|
解法一：配方法：
∵y=-
x2-2x-3=-1 4
（x+4）2+1，1 4
∴顶点坐标为（-4，1）．
解法二：公式法：
由y=-
x2-2x-3可知，1 4
-
=-b 2a
=-4，-2 2×(-
)1 4
=4ac-b2 4a
=1，4×(-
)×(-3)-(-2)21 4 4×(-
)1 4
∴顶点坐标为（-4，1）．
故本题答案为：（-4，1）．
| 根据短文内容，选词填空。 | |
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| Alice is from Australia. She 1 to our school yesterday. So our teacher let me 2 her around our school this morning. At about nine I 3 her at the gate. When she came, we walked into our school along the road. I introduced the teaching buildings, office buildings, the library, and the gym to her. When we finished 4 , she said that our school was very big and beautiful, and she liked it very much. She 5 she could study here all the time. |