1. D (đọc là /ɒ/, còn lại là /əʊ/) (nếu gạch chữ "o")

2. B (đọc là /s/, còn lại là /z/) (nếu gạch chữ "s")

1. C

2. C

3. B

4. A

1. D

2. B

3. C

4. D

5. D

6. A

7. B

8. C

\(x^2-2mx+m^2-2m+2=0\left(1\right)\)

a) Thay m = 2 vào pt (1) ta được:

\(x^2-2.2x+2^2-2.2+2=0 \)

\(\Leftrightarrow x^2-4x+2=0\left(a=1;b=-4;c=2\right)\)

Ta có: \(\Delta=b^2-4ac=\left(-4\right)^2-4.1.2=8\)

Vì △ > 0 nên pt có 2 nghiệm phân biệt:

\(x_1=\dfrac{-b+\sqrt{\Delta}}{2a}=\dfrac{-\left(-4\right)+\sqrt{8}}{2.1}=2+\sqrt{2}\)

\(x_2=\dfrac{-b-\sqrt{\Delta}}{2a}=\dfrac{-\left(-4\right)-\sqrt{8}}{2.1}=2-\sqrt{2}\)

Vậy khi m = 2 thì nghiệm của pt (1) là x₁ = \(2+\sqrt{2}\) ; x₂ = \(2-\sqrt{2}\)

b) \(x^2-2mx+m^2-2m+2=0\left(1\right)\)

\(\left(a=1;b'=-m;c=m^2-2m+2\right)\)

Ta có: \(\Delta'=b'^2-ac=\left(-m\right)^2-1.\left(m^2-2m+2\right)=m^2-m^2+2m-2=2m-2\)

Để phương trình (1) có nghiệm thì: \(\Delta\ge0\)

                                                     \(\Rightarrow2m-2\ge0\)

                                                     \(\Leftrightarrow2m\ge2\)

                                                     \(\Leftrightarrow m\ge1\)

Vậy m ≥ 1 thì phương trình có nghiệm nên áp dụng hệ thức Vi ét:

\(x_1+x_2=\dfrac{-b}{a}=\dfrac{-\left(-2m\right)}{1}=2m\) \(\left(2\right)\)

\(x_1x_2=\dfrac{c}{a}=m^2-2m+2\) \(\left(3\right)\)

Ta có: \(x_1^2+x_2^2=x_1+x_2+8\)

   \(\Leftrightarrow\left(x_1^2+2x_1x_2+x_2^2\right)-2x_1x_2-x_1-x_2=8\)

   \(\Leftrightarrow\left(x_1+x_2\right)^2-2x_1x_2-\left(x_1+x_2\right)=8\) \(\left(4\right)\)

Thay (2), (3) vào (4) ta được:

\(\left(2m\right)^2-2\left(m^2-2m+2\right)-2m=8\)

\(\Leftrightarrow4m^2-2m^2+4m-4-2m-8=0\)

\(\Leftrightarrow2m^2+2m-12=0\)

\(\Leftrightarrow m^2+m-6=0\) \(\left(a=1;b=1;c=-6\right)\)

Ta có: \(\Delta=b^2-4ac=1^2-4.1.\left(-6\right)=25\)

Vì △ > 0 nên pt có 2 nghiệm phân biệt:

\(m_1=\dfrac{-b+\sqrt{\Delta}}{2a}=\dfrac{-1+\sqrt{25}}{2.1}=2\left(TMĐK\right)\)

\(m_2=\dfrac{-b-\sqrt{\Delta}}{2a}=\dfrac{-1-\sqrt{25}}{2.1}=-2\left(loại\right)\)

Vậy m = 2 thì phương trình (1) có 2 nghiệm phân biệt x₁, x₂ thỏa mãn: \(x_1^2+x_1^2=x_1+x_2+8\)

Mono said Truong Thi Ha would feel shy because she often sobbed documents to sell.

I asked my friend if he/she had had a car accident the previous month.

15. What is the capital city of Spain? – I’m not sure, but it  ______ Madrid.

    A. might                    B. might be                C. will                        D. will be

16. This wahing machine is fully ______ . All you have to do is put your clothes in and press this button.

      A. automate          B. auto                       C. automatically            D. automatic    

17. You will get a good seat if you ______ first.                

      A. came                 B. come                       C. comes                      D. will come

18. They are on holiday for two weeks, ______ they won’t be here tomorrow

      A. but                    B.  and                         C. so                            D. because 

19. Playing sports ______ me get fitter now.       

       A.helps                 B. will help                   C. helping                  D. help

20. Army: “ Let’s go to Ha Noi.”– Jim: “______ ”

      A. No, thanks          B. No, let’s go to Hai Phong.    C. What about food?    D. Yes, we do.                  

=> It is/ has been two years since I went to Singapore.

is

1. A

2. D

3. A

4. A

21. A

22. D

23. B

24. D

25. C

V

1. It's emojis

2. In 20 years

3. People of all ages

4. They help people communicate their emotions effectively regardless of the language they speak.