5. A

V. 

1. Flying cars will be used to travel across the globe someday

2. Developed contries have less population problem than developing countries

3. It is about 120km from Vung Tau to HCM City

4. I used to walk to school when I was a student

5. If we don't keep the environment clean, we'll suffer from pollution

6. In spite of having a map, we had difficulty in finding her house

VI.

1. He used to go hunting in forests when he was younger

2. 

3. It is better to eat less food containing fat and suger

4. Turn left and you will see the sourvenir shop on your right

a. \(\dfrac{x-1}{x+3}-\dfrac{x}{x-3}=\dfrac{7x-3}{9-x^2}\) (đk: x\(\ne\)3; x\(\ne\)-3)

<=> (x-1)(x-3)-x(x+3)=3-7x (xin lỗi mình lười đánh máy quá nên làm tắt chút, khử mẫu và đổi dấu cả tử cả mẫu ở vế phải nhé)

<=> x\(^2\)-4x+3-x\(^2\)-3x-3+7x=0

<=> 0=0 (luôn đúng với mọi x)

9. No sooner had he got home than it began to rain

Sorry :< Mình làm hơi ẩu :<<<

1. If she doesn't quit smoke, she'll die

2. It is a two-week holiday

3. Despite his richness, Peter never helped the poor

4. If farmer added fertilizers, the soil wouldn't become poor

5. Sciences are oftens been looked as experts

6. Because of being so proud, he couldn't admit that he was wrong

7. I'm not used to going into city by car

8. Never will Mr. Quynh forget his student

9. No sooner than he got home that it began to rain

10. The children whose parents work late are taken home by bus

I. 

1, D

2, C

3. A

II.

1. C

2. B

III.

1. B

2. A

3. B

4. B

5. B

IV.

1. C

2. A

3. C

4. B

pt <=> 2x\(^2\)-7x-4x+14=0

<=> 2x\(^2\)-11x+14=0

<=> 2x\(^2\)-4x-7x+14=0

<=> (2x-7)(x-2)=0

<=> \(\left[{}\begin{matrix}x=2\\x=\dfrac{7}{2}\end{matrix}\right.\)

"Không lớn hơn 2020" thì được bằng 2020 chứ nhỉ?

pt <=> (3x-1)(x\(^2\)+2-7x+10)=0

<=> (3x-1)(x\(^2\)-7x+12)=0

<=> \(\left[{}\begin{matrix}3x-1=0\\x\text{​​}^2-7x+12=0\end{matrix}\right.\)

<=> \(\left[{}\begin{matrix}x=\dfrac{1}{3}\\\left(x-4\right)\left(x-3\right)=0\end{matrix}\right.\)

<=> \(\left[{}\begin{matrix}x+\dfrac{1}{3}\\x=4\\x=3\end{matrix}\right.\)

hpt <=> \(\left\{{}\begin{matrix}\dfrac{8}{10}x+\dfrac{8}{10}y=400\\\dfrac{8}{10}x+\dfrac{9}{10}y=420\end{matrix}\right.\)

<=>\(\left\{{}\begin{matrix}x+y=500\\\dfrac{1}{10}y=20\end{matrix}\right.\)

<=> \(\left\{{}\begin{matrix}x+y=500\\y=200\end{matrix}\right.\)

<=>\(\left\{{}\begin{matrix}x=300\\y=200\end{matrix}\right.\)

4. B

5. A

6. C

7. C

8. B

9. B

10. A

11. C

12. 

13. A

14. 

15. C