1. C. \(16x^2\left(x-y\right)\)\(-10y\left(y-1\right)\)\(=-2\left(y-x\right)\)\(\left(8x^2+5y\right)\)

2. C. \(\left(x-y\right)\left(x-y-3\right)\)

3. D. \(\left(x-2\right)\left(x+1\right)\)

4. C. \(y\left(x-2\right)\)\(5x\left(x-3\right)\)

5. D. \(3\left(x-2y\right)\)

Nếu lấy 50 lít thùng 1 sang 2 thì 2 hơn 1 16 lít =>2 thúng sẽ = nhau khi bớt đi 16 lít vay ta lấy 398-16=382lít 
rồi lấy 382 : 2 ra đc 191 lít 
số lít nước lấy bớt đi để 2 =1 là
50-16=34 lít 
số lít ở thùng 1 là
191+50=241 lít 
số lít ở thùng 2 là
398-241=157 lít 

1. can't you do better than that ?

=> is that the best you can do?

2. why don't we go shopping this weekend ?

=> shall we go shopping this weekend?

3. I don't want to do anything too energetic today

=> I don't feel like doing anything too energetic today.

4. it isn't necessary for students to wear uniforms on Wednesday

=> students don't have to wear uniforms on Wednesday.

5. she teaches English well

=> she is a good teacher.

6. she feels comfortable to watch TV

=> Watching TV makes her comfortable.

7. my new jeans are more expensive than yours

=> my new jeans aren't as cheap as yours.

8. we spent a whole day looking for these old pictures

=> it took us a whole day to look for these old pictures.

9. when did you buy the coputer ?

=> how long is it since you bought the computer?

10. what is the distance between your hometown and your school ?

=> how far is it from your hometown to school?

1) 2C₂H₆ + 7O₂ ---> 4CO₂ + 6H₂O

2) 2C₆H₆ + 15O₂ ---> 12CO₂ + 6H₂O

3) Fe₃O₄ + 8HCl ---> FeCl₂ + 2FeCl₃ + 4H₂O

4) Fe₂O₃ + 3CO ---> 2Fe + 3CO₂

5) Fe₃O₄ + 4CO ---> 3Fe + 4CO₂

6) 4FeO + O₂ ---> 2Fe₂O₃

7) 4Fe₃O₄ + O₂ ---> 6Fe₂O₃

8) 2Mg(NO₃)₂ ---> 2MgO + 4NO₂ + 4O₂

9) 4Fe(NO₃)₃ ---> 2Fe₂O₃ + 12NO₂ + 3O₂

10) 4NO₂ + O₂ + 4H₂O ---> 4HNO₃

11) 4Fe(OH)₂ + O₂ + 2H₂O ---> 4Fe(OH)₃

12) S + 2H₂SO₄ ---> 3SO₂ + 2H₂O

13) 3AgNO₃ + 2H₂O ---> 3Ag + 4HNO₃ + O₂

14) FexOy + HCl ---> FeCl2y/x + H2O

FeO + 2HCl ----> FeCl₂ + H₂O

1) FeS₂ + 18HNO₃ ---) Fe(NO₃)₃ + 2H₂SO₄ + 15NO₂ + 7H₂O

2) 4FeS + 7O₂ --) 2Fe₂O₃ + 4SO₂

3) C₃H₈ + 5O₂ --) 3CO₂ + 4H₂O

4) 2Al + 6H₂SO₄ --) Al(SO₄)₃ + 3SO₂ + 6H₂O

a) When does Chi have English?

- She has it on Wednesday.

b) When do you have Math?

- I have Math on Friday.

c) When do we have Geography?

- We have it on Monday.

d) When do Nga and Mai have history?

- They have it on Thursday.

Xét tam giác AMB và tam giác AMC có:

góc B= góc C (gt)

AB = AC (gt)

BM = CM (gt)

=> Tam giác AMB = tam giác AMC (c-g-c)