Tất cả k dưới đây đều là \(k\in Z\)

6.

\(\Leftrightarrow\sqrt{3}cot\left(3x-\dfrac{\pi}{3}\right)=1\)

\(\Leftrightarrow cot\left(3x-\dfrac{\pi}{3}\right)=\dfrac{1}{\sqrt{3}}\)

\(\Leftrightarrow cot\left(3x-\dfrac{\pi}{3}\right)=cot\left(\dfrac{\pi}{3}\right)\)

\(\Leftrightarrow3x-\dfrac{\pi}{3}=\dfrac{\pi}{3}+k\pi\)

\(\Leftrightarrow3x=\dfrac{2\pi}{3}+k\pi\)

\(\Leftrightarrow x=\dfrac{2\pi}{9}+\dfrac{k\pi}{3}\) 

7.

\(\Leftrightarrow\sqrt{3}tan\left(3x-15^0\right)=-1\)

\(\Leftrightarrow tan\left(3x-15^0\right)=-\dfrac{1}{\sqrt{3}}\)

\(\Leftrightarrow tan\left(3x-15^0\right)=tan\left(-30^0\right)\)

\(\Leftrightarrow3x-15^0=-30^0+k180^0\)

\(\Leftrightarrow3x=-15^0+k180^0\)

\(\Leftrightarrow x=-3^0+k60^0\)

8.

\(\Leftrightarrow\sqrt{3}cot\left(3x-30^0\right)=1\)

\(\Leftrightarrow cot\left(3x-30^0\right)=\dfrac{1}{\sqrt{3}}\)

\(\Leftrightarrow cot\left(3x-30^0\right)=cot\left(60^0\right)\)

\(\Leftrightarrow3x-30^0=60^0+k180^0\)

\(\Leftrightarrow3x=90^0+k180^0\)

\(\Leftrightarrow x=30^0+k60^0\)

Viết thành câu hoàn chỉnh bằng từ gợi ý: 

1. The doctor say / that he / done all he could / save Kumar's life.

→ The doctor said that he had done all he could to save Kumar's life. 

2. Mrs. Vasanthi said / her husband / she / about to go / sleep when Mrs/ Bala called

→ Mrs. Vasanthi said that she was about to go to sleep when Mrs. Bala called her husband

3. Kenneth said / salmon swim upstream / spawn.

→ Kenneth said that salmon swim upstream to spawn.

4. The man said / the elections would / held / the end / the month

→ The man said that the elections would be held at the end of the month.

5. Ruilan told Lily / she leave / her handkerchief / her house the previous day

→ Ruilan told Lily that she had left her handkerchief at her house the previous day.

6. Mrs. Bai remind / Michelle / check the stock before she pay / for it

→ Mrs. Bai reminded Michelle to check the stock before she paid for it

7. Junisha asked / that shop across / street sold chocolate ice cream

→ Junisha asked if the shop across the street sold chocolate ice cream.

8. Shijin told Linchong / go / his house that night / play computers games

→ Shijin told Linchong to go to his house that night to play computer games.

9. Peter told his brother that pair / shoes / his

→ Peter told his brother that the pair of shoes was his.

10. Robin suggested / they buy a bouquet / flowers / Grace / cheer her up.

→ Robin suggested that they buy a bouquet of flowers for Grace to cheer her up.
 

Viết thành câu hoàn chỉnh bằng từ gợi ý: 

1. The catfish / we ate yesterday / not fresh.

→ The catfish we ate yesterday was not fresh.

2. Could / please tell me where / women's clothes are ?

→ Could you please tell me where the women's clothes are?

3. Susan run / out / the house fling / open the gate / jump / the car

→ Susan ran out of the house, flung open the gate, and jumped into the car.

4. Yesterday as I / on my way home / school, I find / this adorable puppu in / drain

→ Yesterday, as I was on my way home from school, I found this adorable puppy in the drain.

5. Sure he / our primary school teacher ?

→ Are you sure he is our primary school teacher?

6. Here / some things I would like you / buy / the market 

→ Here are some things I would like you to buy at the market.

7. This programme is aim / at teaching pupils Asian values / culture

→ This programme is aimed at teaching pupils Asian values and culture.

8. Yuming's mother write / a letter / Mrs. Lu / explain that yuming / not take part / any sports

→ Yuming's mother wrote a letter to Mrs. Lu explaining that Yuming would not take part in any sports.

9. Some people think / Jinlong should / given another chance

→ Some people think Jinlong should be given another chance.

10. The three characters / this story / sisters / were separate / at birth.

→ The three characters in this story were sisters who were separated at birth.

\(a,\dfrac{-3}{7}-x=\dfrac{8}{9}\\ =>x=-\dfrac{3}{7}-\dfrac{8}{9}\\ =>x=-\dfrac{83}{63}\)

\(b,\left(\dfrac{3}{10}-x\right):\dfrac{2}{5}=\dfrac{3}{5}\\ =>\dfrac{3}{10}-x=\dfrac{3}{5}\text{×}\dfrac{2}{5}=\dfrac{6}{25}\\ =>x=\dfrac{3}{10}-\dfrac{6}{25}=\dfrac{3}{50}\)

a: =>x=-3/7-8/9=-83/63

b: \(\Leftrightarrow\left(\dfrac{3}{10}-x\right)=\dfrac{3}{5}:\dfrac{2}{5}=\dfrac{3}{2}\)

=>x=3/10-3/2=-6/5

c: \(\Leftrightarrow\left(x-\dfrac{1}{2}\right)^2=4\)

=>x-1/2=2 hoặc x-1/2=-2

=>x=5/2 hoặc x=-3/2

d: =>1/8x+1/2=5/2-3/4=10/4-3/4=7/4

=>1/8x=7/4-1/2=5/4

=>x=10

\(a:\dfrac{-3}{7}-x=\dfrac{8}{9}\\ x=\dfrac{-3}{7}-\dfrac{8}{9}\\ x=-\dfrac{83}{63}\\ b:\left(\dfrac{3}{10}-x\right):\dfrac{2}{5}=\dfrac{3}{5}\\ \dfrac{3}{10}-x=\dfrac{3}{5}\cdot\dfrac{2}{5}\\ \dfrac{3}{10}-x=1\\ x=\dfrac{3}{10}-1\\ x=-\dfrac{7}{10}\\ c:\dfrac{1}{36}\cdot\left(x-\dfrac{1}{2}\right)^2=\dfrac{1}{9}\\ \left(x-\dfrac{1}{2}\right)^2=\dfrac{1}{9}:\dfrac{1}{36}\\ \left(x-\dfrac{1}{2}\right)^2=4\\ \left(x-\dfrac{1}{2}\right)^2=2^2;-2^2\\ x-\dfrac{1}{2}=2\\ x=2+\dfrac{1}{2}\\ x=\dfrac{5}{2}\\ x-\dfrac{1}{2}=-2\\ x=-2+\dfrac{1}{2}\\ x=-\dfrac{3}{2}\\ x=\left\{\dfrac{5}{2};-\dfrac{3}{2}\right\}\)

a. Phương trình hoành độ giao điểm:

\(3x-5=-2x\)

\(\Leftrightarrow5x=5\)

\(\Rightarrow x=1\)

Thế vào \(y=3x-5\Rightarrow y=3.1-5=-2\)

Vậy \(A\left(1;-2\right)\)

b. Gọi phương trình d có dạng \(y=ax+b\)

Do d song song \(d_1\Rightarrow a=1\Rightarrow y=x+b\)

Do d qua A nên: \(y_A=x_A+b\Leftrightarrow-2=1+b\Rightarrow b=-3\)

Vậy pt d có dạng: \(y=x-3\)

1 She said that she was coming 

2 She said that she wouldn't see me the following day 

3 She said that he worked in a bank 

4 She said that he was living in Paris for a few months

5 Lan said that she would be very busy the next day 

6 Thu said that all the students would have a meeting the following sunday 

7 Tam said that she could swim acroos that river 

8 His sister said that she didn't buy that book 

9 The boy said that they had to try their best to win the match 

10 Her father said to her that she could go to the movies with her friends 

11 Her classmate said that Lan was the most intellligent girl in their class 

12 The teacher said that the sun rised in the east

Độ dài chiều cao của hình bình hành là :

   23:(2+3)×2=41523:(2+3)×2=415

Độ dài cạnh đáy của hình bình hành là :

  23−415=2523−415=25

Diện tích của hình bình hành là :

  425×25=8125425×25=8125(đvdt)

       Đáp số :...