抛物线y=（x-1）2+3的对称轴是[ ] A.直线x=1 B.直线x=3 C.

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问题选择题

抛物线y=（x-1）²+3的对称轴是[ ]

A.直线x=1

B.直线x=3

C.直线x=-1

D.直线x=-3

答案

答案：A

选择题

请选择与句子内容相符的图片。
( ) 1. He had a cold last night.	A.
( ) 2. A big ball bumped his head.	B.
( ) 3. He rode a bike last weekend.	C.
( ) 4. She played the flute yesterday.	D.
( ) 5. She fell off her bike yesterday.	E.

解答题

甲、乙两班各派2名同学参加年级数学竞赛，参赛同学成绩及格的概率都为0.6，且参赛同学的成绩相互之间没有影响，求：

（1）甲、乙两班参赛同学中各有1名同学成绩及格的概率；

（2）甲、乙两班参赛同学中至少有1名同学成绩及格的概率．