已知y=x2-2x-3，当x=______时，y的值是-3．_爱下问搜题

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问题填空题

已知y=x²-2x-3，当x=______时，y的值是-3．

答案

据题意得，

x²-2x-3=-3

∴x²-2x=0

∴x（x-2）=0

∴x₁=0，x₂=2

∴当x=0或2时，y的值是-3．

阅读理解

1. Open time:8:30 a. m. -4:00 p. m. from Monday to Friday

2. No talking.

3. No food.

4. No listening to music.

5. No photos.

6. No taking books out without permission (允许) .

7. Keep the library books for one week.

8. Return books on time.36. We can read books .

9. Renew (续借) books on time.

10. Pay for the lost books.

1. We can read books .

A. at 8:00 a. m. on Monday

B. at 9:00 a. m. on Sunday

C. at 3:15 p. m. on Thursday

D. at 4:30 p. m. on Wednesday

2. We can't according to the rules.

A. borrow books

B. renew books

C, take books out without permission

D. read books

3. We have to if we lose library books.

A. pay for them

B. buy them

C. return them

D．renew them

4. It's not polite（礼貌）to in the library.

A. retum books on time

B．renew books on time

C．borrow books

D．talk loudly

5. We must leave the library____.

A. at 2:00 p.m.

B. before 4:00 p.m.

C. after 4:00 p.m.

D. at 8:30 a.m.

单项选择题

北京故宫的平面中轴对称、三朝五门、前朝后寝中的“三朝五门”的五门从南向北依次是( )。

A．正阳门、 * * 、太和门、乾清门、神武门

B．大清门、 * * 、端门、午门、太和门

C． * * 、端门、太和门、乾清门、地安门

D． * * 、大清门、午门、太和门、乾清门