\(\sqrt{4x^2-4x+1}-\sqrt{4x^2+4x+1}\)

a.\(\sqrt{19-6\sqrt{2}}\)                         b.\(\sqrt{11-6\sqrt{2}}\)                c.\(\sqrt{9-6\sqrt{2}}\)

d.\(\sqrt{21+12\sqrt{3}}\)                        e.\(\sqrt{57-40\sqrt{2}}\)

bài 1: rút gọn bthuc

a.\(\dfrac{a+\sqrt{a}}{\sqrt{a}}\)                            b.\(\dfrac{\sqrt{\left(x-3\right)^2}}{3-x}\)

b2: rút gọn

a.\(\dfrac{\sqrt{9x^2-6x+1}}{9x^2-1}\)                          b.4-x-\(\sqrt{4-4x+x^2}\)                c.\(\sqrt{4x^2-4x\text{x^2 +2*x-3 >0}}-\sqrt{4x^2+4x+1}\)

x^2 +2*x-3 >0

biểu thức sau đây xác định với giá trị nào của x

\(\sqrt{\dfrac{4}{2x+3}}\)    \(\sqrt{\dfrac{2x-1}{2-x}}\)

I. Complete the sentences, putting the verbs into the past continuous or past simple:

11. Albert Einstein (die) ____died___ in 1955.

12. Tom (go) ____went___ to the post office twice yesterday.

13. He (fall) ___fell____ while he (go) _was going______ down the stairs

14. What ___did____ she (do) when you (arrive) ___arrived____ there? She (write) ___writed____ a letter

15. She (have) _______ her bath while her sister (get) _______ the breakfast ready

16. I (go) _______ to ask you to help me, but you (sleep) _______ so peacefully when I (look) _______ into your room that I (decide) _______ to do it alone

17. I (look) _______ up at the sky, dark clouds (gather) _______

18. Just as I (write) _______ the letter, the inkpot (fall) _______ over

19.  Mr. Nam (cook) _______ dinner when we (arrive) _______

20. What _______  (you/do) when I (telephone) _______ you last night?

II. Complete the sentences, putting the verbs into the correct tenses:

11. Why are you under the table? You (look) _______ for something?

12. _______ You (watch) TV last night? No, I (have) _______ supper and (go) _______ straight to bed

13. I (not like) _______ staying at hotels, but last summer, we (spend) _______ a few days at a very nice hotel by the sea.

14. Linda (be) _______ busy when we (go) _______ to see her yesterday. She (study) _______ for an exam. We (not want) _______ to disturb her, so we (not stay) _______ very long

15. When I first (tell) _______ Tom the news, he (not believe) _______ me. He (think) _______ that I (joke) _______

16. We usually (go) _______ to Spain on holiday, but this year we (go) _______ to France

17. We can go out now. It (not rain) _______ any more

18. The sun (warm) _______ the air and (give) _______ us light

19. What speed _______ the car (do) at the time of the accident?

20. They (study) _______ in the library when the fire alarm (go) _______ off

III. Cirle the best option to complete each sentence:

1. She usually _____ two hours a day

a. work                            b. is working                   c. works                 d. working

2. Don’t make noise. My mother _________ with her friends

a. is talking            b. was talking                  c. talks                             d. talked

3. Listen! They _________ about the exhibition . Let’s join them

a. talk                     b. talked                 c. are talking                    d. have talked

4. Where _____ your sister born?

a. were                             b. was                              c. did                     d. is

5. We _____ have white wine, but we _____ red wine

a. didn’t/had          b. don’t/had           c. did/didn’t           d. didn’t/have

6. When did you _________ see him?

a. recently              b. already               c. last                     d. lately

7. I _________ a bath when the phone rang

a. was having                   b. had                    c. am having                    d. have

8. I _____ her two week ago

a. seen                              b. was seeing                   c. saw                    d. have seen

9. I _____ to his house in 1991

a. moved                b. have been moving       c. have moved                 d. was moving

10. He came into the room while they _________ television

a. have watched     b. watched             c. were watching    d. have been watching

11. I fell asleep when I _____ television

a. am watching       b. am being watched        c. was watching     d. All are correct

12. They _____________ last week

a. didn’t come        b. came not            c. don’t come                   d. did come

13. Where are Geoff and Anne? _____________ in the garden

a. They’re sitting    b. They sitting                  c. There sitting       d. They’re siting

14. It’s very cold today and _____

a. It’s snowing                 b. it snows             c. its snowing                   d. it snowing

15. She goes to the library twice a week. She _____________ read books there

a. never                  b. usually               c. rarely                  d. once

16. At nine o’clock yesterday morning, we _____________ for the bus

a. are waiting                   b. waited                c. were waiting      d. was waiting

17. Tom _________ his hand when he was cooking the dinner

a. burnt                  b. was burning                 c. has burnt            d. had burnt

18. He _________ me every Sunday, and we often go fishing together

a. came to see                   b. comes to see      c. will be coming to seed. All answer are correct

19. The phone rang while she _________ dinner

a. cooks                 b. was cooking      c. is cooking                    d. has cooked

20. My sister _________ trouble with her motobike now, so she has to take the bus to work

a. have                             b. is having            c. was having                   d. had

21. When my mum got home, _________

a. the dinner be cooked                        b. I was cooking dinner

c. I am cooking dinner                         d. the dinner deing cooked

22. Emma and Katie usually _________ their grandmother at weekends

a. have visited                  b. visits                  c. visit                    d. are visiting

23. Peter was reading a book by Mark Twain _________ his friends came

a. while                  b. when                  c. during                d. if

24. Look! That boy _________ an elephant over there

a. fed                     b. was feeding                 c. feeds                  d. is feeding

25. He _________ in London at the moment

a. studies                b. has studied                   c. is studying                    d. will study

b1 : số nào có căn bậc 2

a,\(\sqrt{3}\)       b.1,3        c.-0.1     d.-\(\sqrt{4}\)

b2: tính giá trị gần đúng của nghiệm mỗi phương trình sau( lm tròn đên chữ sỗ thập phân thứ 3 )

a.x²=5                    b.x²=2.5                     c.x²=\(\sqrt{5}\)

2x²+3x+1=0