Mk có giải ở câu: https://hoc24.vn/hoi-dap/question/173641.html đó bạn, kết quả là bằng -2.

Từ 1 đến 100 có 100 số. Như vậy, số cặp số là:

100 : 2 = 50 (cặp)

Mỗi cặp số có tổng bằng:

1 + 100 (2 + 99) (3 + 98) ... = 101

Kết quả của phép tính là:

101 . 50 = 5050

Đáp số: 5050

Vì x và y là hai đại lượng tỉ lệ thuận nên:

\(\frac{y_1}{x_1}=\frac{y_2}{x_2}\) = k (k \(\ne\) 0)

và \(x_1=6;x_2=-9\)

Áp dụng tính chất dãy tỉ số bằng nhau, ta có:

\(\frac{y_1}{x_1}=\frac{y_2}{x_2}=\frac{y_1-y_2}{x_1-x_2}=\frac{10}{6-\left(-9\right)}=\frac{10}{15}=\frac{2}{3}\)

\(\frac{y_1}{x_1}=\frac{2}{3}\Rightarrow y_1=\frac{2}{3}.x_1=\frac{2}{3}.6=4\)

\(\frac{y_2}{x_2}=\frac{2}{3}\Rightarrow y_2=\frac{2}{3}.x_2=\frac{2}{3}.\left(-9\right)=-6\)

Vậy: \(y_1+y_2=4+\left(-6\right)=-2\)

Xin lỗi, mk sai một số chỗ, cho mk sửa lại.

1. She received a lettter ...from..... her mother last week.

2. Minh had an appointment ......at...... 10.30 this morning.

3. The dentist looked .....at....... my teeth and told me not to worry .

4. Dr. Lai fills in cavity ....in...... Minh's tooth.

5. What's wrong ......with...... him ?

6. Thank you ......for...... your letter.

7. Are you scared .....of...... seeing the doctor?

8. I hope you are taking care ...of.......... yourself.

9. My father is sitting .....in........... Dr Lai's surgery.

10. The nurse smiles ......at....... Nam and says, "Don't worry, Nam."

1. She received a lettter ...from..... her mother last week.

2. Minh had an appointment .....at....... 10.30 this morning.

3. The dentist looked .....at....... my teeth and told me not to worry .

4. Dr. Lai fills in cavity ....in...... Minh's tooth.

5. What's wrong .....with....... him ?

6. Thank you ......for...... your letter.

7. Are you scared .....of...... seeing the doctor?

8. I hope you are taking care ...to.......... yourself.

9. My father is sitting ......on.......... Dr Lai's surgery.

10. The nurse smiles .....with........ Nam and says: "Don't worry, Nam."

1. Fill in each gap with one suitable word :

I live (1) in Ha Noi. It is (2) a busy city. The streets (3) are crowed and there are traffic jams in the rush hour. I am somtimes late for school because of the traffic jams. Some people don't (4) obey the traffic rules. They pass the red traffic light, wear no helmets, ... Therefore, sometimes there (5) are accidents.

2. Word form :

1. The chilren were frightened by the stories about ghosts. (FRIGHTEN)

2. It is illegal to use gun without permission. (LEGAL)

3. Be careful ! A car is coming ! (CARE)

4. Have you got a driving lisence ? (DRIVE)

5. Stop in front of the zebra crossing when the traffic light turns into red. (CROSS)

6. It is surprised to meet you here. (SURPRISE)

7. My daughter felt surprised at my gift on her birthday. (SURPRISE)

8. She felt depressed when hearing that she was turned down for the job. (DEPRESS)

1. He is so young. His acting is excellent.

=> Although he is so young, his acting is excellent.

2. It was noisy. The children slept well.

=> It was noisy, but despite the children slept well.

3. All critics said this film is really boring. I was so interested in it.

=> All critics said this film is really boring. Nevertheless, I was so interested in it.

4. The film poster is fascinating. I don't want to see this film.

=> I don't want to see this film in spite of the film poster is fascinating.

5. She prepared carefully for the casting. She wasn't chosen.

=> She prepared carefully for the casting. However, she wasn't chosen.

6. Although our plan is careful, we made some mistakes.

=> Our plan is careful, but despite we made some mistakes.

7. We can get to the art gallery in half an hour

=> It only takes half an hour to get to the art gallery.

Xin lỗi, mk ấn nhầm.

1.family/have/because/like/all evening/Linh's/a TV/ they/talk/doesn't /to

=> Linh's family doesn't have a TV because they like to talk all evening.

2.telling/I/Hanh/doesn't/lies/neither/like/and/do

=> Hanh doesn't like telling lies and neither do I.

3.her/His/sister/her/gift/birthday/bought/15th/for/that/on

=> His sister bought her that gift on her 15th birthday.

4.please/dictionary/your/you/Would/me/lend/English?

=> Would you please lend me your English dictionary?

1.

=> Linh's family

2. telling/I/Hanh/doesn't/lies/neither/like/and/do

=> Hanh doesn't like telling lies and neither do I.

3.her/His/sister/her/gift/birthday/bought/15th/for/that/on

=> His sister bought her that gift on her 15th birthday.

4.please/dictionary/your/you/Would/me/lend/English?

=> Would you please lend me your English dictionary?