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10 tháng 4

Câu 2:

a: Xét ΔDAE và ΔDBE có

DA=DB

EA=EB

DE chung

Do đó; ΔDAE=ΔDBE

b: ΔDAE=ΔDBE

=>\(\hat{DAE}=\hat{DBE}\)

Câu 3:

a: Để ΔABC=ΔADC thì cần có thêm một điều kiện là \(\hat{BAC}=\hat{DAC}\)

b: Để ΔAMB=ΔEMC thì cần có thêm một điều kiện là MA=ME

c: Để ΔCAB=ΔDBA thì cần có thêm điều kiện là CA=DB

17 tháng 3 2023

a nhờ... thuyền

b bình minh

c qua bao năm tháng 

d bắng... mình 

e chiều chiều , trên bãi thả

f lát sau, để trả thù

g khi... ngỗ

h đêm... quá

nhé

 

 

4 tháng 7 2016

\(\left(x-6\right)^2=9=3^2=\left(-3\right)^2\)

\(=>\orbr{\begin{cases}x-6=3\\x-6=-3\end{cases}=>\orbr{\begin{cases}x=9\\x=3\end{cases}}}\)

Vậy...............

\(\left(x-6\right)^2=9\)

\(=>\sqrt{\left(x-6\right)^2}=\sqrt{9}\)

\(=>x-6=3\)

\(=>x=6+3\)

\(=>x=9\)

Ủng hộ nha

18 tháng 4

a: CB//DA

=>\(\hat{CBA}+\hat{BAD}=180^0\) (hai góc trong cùng phía)

=>\(\hat{BAD}=180^0-125^0=55^0\)

b: Ta có: \(\hat{BAD}+\hat{DAM}=\hat{BAM}\) (tia AD nằm giữa hai tia AB và AM)

=>\(\hat{DAM}=90^0-55^0=35^0\)

Xét ΔMNA có \(\hat{MNA}+\hat{MAN}=35^0+55^0=90^0\)

nên ΔMNA vuông tại M

=>MN⊥MA

c: HI⊥AM

BA⊥ MA

Do đó: HI//BA

=>\(\hat{CHI}=\hat{CBA}\) (hai góc đồng vị)

25 tháng 2 2021

I)1.B

2.B

3.C

4.D

5.C

II)

1.B

2.D

3.B

4.B

5.A

6.B

7.tell....way.

8.C

III)

1.isn't teaching

2.drive

3.has

 

13 tháng 4

a: Xét ΔIDE và ΔIAC có

ID=IA

\(\hat{DIE}=\hat{AIC}\) (hai góc đối đỉnh)

IE=IC

Do đó: ΔIDE=ΔIAC

=>\(\hat{IDE}=\hat{IAC}\)

mà hai góc này là hai góc ở vị trí so le trong

nên DE//AC

ΔIDE=ΔIAC

=>DE=AC

b: Xét ΔIAE và ΔIDC có

IA=ID

\(\hat{AIE}=\hat{DIC}\) (hai góc đối đỉnh)

IE=IC

Do đó: ΔIAE=ΔIDC

=>\(\hat{IAE}=\hat{IDC}\)

mà hai góc này là hai góc ở vị trí so le trong

nên AE//DC

=>AE//DB

ΔIAE=ΔIDC

=>AE=DC

ΔABC cân tại A

mà AD là đường cao

nên D là trung điểm của BC

=>DB=DC

=>DB=AE
Ta có: AE//BC

AD⊥BC

Do đó: AE⊥ AD

Xét ΔEAD vuông tại A và ΔBDA vuông tại D có

EA=BD

AD chung

Do đó: ΔEAD=ΔBDA

=>ED=BA

mà BA=AC
nên ED=AC
Xét ΔEBD và ΔADC có

ED=AC

\(\hat{EDB}=\hat{ACD}\) (hai góc đồng vị, ED//AC)

DB=CD

Do đó: ΔEBD=ΔADC

=>EB=AD và \(\hat{EBD}=\hat{ADC}\)

=>\(\hat{EBD}=90^0\)

=>BE⊥BC

c: Xét ΔJEA và ΔJDB có

\(\hat{JEA}=\hat{JDB}\) (hai góc so le trong, EA//DB)

EA=DB

\(\hat{JAE}=\hat{JBD}\) (hai góc so le trong, EA//DB)

DO đó: ΔJEA=ΔJDB

=>JA=JB và JE=JD

JA=JB

=>J là trung điểm cua AB


d: Xét ΔADB có

J,I lần lượt là trung điểm của AB,AD

=>JI là đường trung bình của ΔADB

=>JI//BD và \(JI=\frac{BD}{2}\)

JI//BD

=>JI//BC

\(JI=\frac{BD}{2}\)

=>\(JI=\frac12BD=\frac12\cdot\frac12\cdot BC=\frac14\cdot BC\)

e: ΔEKD vuông tại K

mà KJ là đường trung tuyến

nên \(KJ=\frac{ED}{2}=\frac{AB}{2}\)

Xét ΔKAB có

KJ là đường trung tuyến

KJ=AB/2

Do đó: ΔKAB vuông tại K

=>\(\hat{AKB}=90^0\)

3 tháng 7 2019

bạn xem lại đề đc k

3 tháng 7 2019

hạng tử cuối là \(2^{2019}\)

đúng ko bạn

28 tháng 7 2023

a: Xét tứ giác BGCK có

M là trung điểm chung của BG và CK

=>BGCK là hbh

=>BG//CK và BK//CG

=>BK vuông góc AB và CK vuông góc CA

góc ABK+góc ACK=90+90=180 độ

=>ABKC nội tiếp đường tròn đường kính AK

=>K thuộc (O)

b:AK là đường kính của (O)

=>O là trung điểm của AK

Xét ΔAKG có

KO/KA=KM/KG

=>OM//AG và OM/AG=KM/KG=1/2

=>AG=2OM

 

có ai biết làm bài này k giúp mình với mình đang cần rất rất gấp mong các bạn giúp cho.I/ Change the following sentences from active into passive form. 1. Somebody has taken my briefcase.=>……………………………………………………………2. The teacher returned our written work to us.=>………………………………………………….3. She had finished her report by...
Đọc tiếp

có ai biết làm bài này k giúp mình với mình đang cần rất rất gấp mong các bạn giúp cho.

I/ Change the following sentences from active into passive form.

1. Somebody has taken my briefcase.=>……………………………………………………………

2. The teacher returned our written work to us.=>………………………………………………….

3. She had finished her report by soon.=>…………………………………………………………….

4. The police have arrested five suspects.=>………………………………………………………….

5. The doctor ordered him to take a long rest.=>…………………………………………………………

6. A group of students have met their friends at the rail way station.

=>……………………………………………………………………..

7. They didn’t allow Tom to take these books home.

=>……………………………………………………………..

8. The teacher won’t correct exercises tomorrow.

=>……………………………………………………………….

9. Marry has operated Tom since 10 o’clock.

=>……………………………………………………………….

10. They didn’t look after the children properly.

=>……………………………………………………………..

11. Nobody swept this street last week.=>…………………………………………………

12. People speak English all over the world.

=>……………………………………………………………

13. Tom was writing two poems.=>…………………………………………………

14. She often takes her dog for a walk.=>…………………………………………………

15. They can’t make tea with cold water.=>…………………………………………………

16. The chief engineer was instructing all the workers of the plan.

=>…………………………………………………………………….

17. Somebody has taken some of my book away.

=>……………………………………………………….

18.. They will hold the meeting before the May Day.

=>………………………………………………………………

19. The boys broke the window and took away some pictures.

=>…………………………………………………………………….

20. People spend a lot of money on advertising everyday.

->……………………………………………………………………..

II. Choose the best answer

1.I come from Canada. Where .................you..................from?

a. do.............come         b. did ...... come     c. are ..........coming        d, have .....come

2. The telephones…………..by Alexander Graham Bell

A. is invented                 B. is inventing                C. Invented           D. was invented

3. The swimming pool .............. at 9 o’clock and ............ at 18.30 everyday.

a. opens............. closes   b. opens ...... closed      c. opened...... closed    d. opened......... closes

4. Three swimmers, Paul, Ed, and Jim, ................ now in competition  for medals.

a. is                       b. has been                      c. had been            d. are

5. Listen ! I .............. somebody knocking at the front door. 

a. am hearing         b. heard                          c. have heard         d. hear

6.. ………………………………………..yet?

A. Have the letters been typed            B. Have been the letters typed

C. Have the letters typed                    D. Had the letters typed

7. At 5 o’clock yesterday evening, I ……………my clothes.

a. am ironing         b. have ironed       c. ironed               d. was ironing.

8. I ………………..along the street when I suddenly heard footsteps behind me.

a. was walking      b. am walking        c. walk                            d. walked.

9. She ………….German for two years.

a. has learnt           b. is learning         c. learn        d. learns.

10. When  I last………..Jane, she ………..to find a job.

a. see/was trying    b. saw/was trying c. have seen/tried            d. saw/tried.

12. French is a…………language to learn than English is.

        A. difficult      B. more difficult       C. most difficult        D. more and more difficult

13. The more polluted air we breathe,…….we get.

          A. the more weaker                  B. the more weak

          C. the weaker                           D. weaker more

14. The more we study, the……we are.

          A. more good                 B. better               C. better than        D. good

15. The more I tried my best to help her, ……….she became.

          A. less lazy                     B. the lazier           C. the more lazy    D. lazier

16. The weather becomes………………

          A. colder with colder                                   B. colder and colder

          C. colder and more colder                            D. more and more cold

17. The more he slept,…………….irritable he became.

          A. the most                     B. the vey more     C. much more       D. the more

18. ………..he worked, the more he earned.

          A. The more hard           B. The hard           C. The harder        D. The hardest

19. ………I get to know Jim, the more I like him.

          A. For more                    B. More                C. The more D. The most

20. The competition makes the price of goods……….

          A. most cheap and cheap                    B. cheaper and cheaper

          C. more cheap and more cheap           D. cheaper and more cheaper

0
có ai biết làm bài này không giúp mình với mình đang cần rất rất là gấp mong các bạn giúp cho , xin cảm ơnII. Choose the best answer1.I come from Canada. Where .................you..................from?a. do.............come         b. did ...... come     c. are ..........coming        d, have .....come2. The telephones…………..by Alexander Graham BellA. is invented                 B. is inventing               ...
Đọc tiếp

có ai biết làm bài này không giúp mình với mình đang cần rất rất là gấp mong các bạn giúp cho , xin cảm ơn

II. Choose the best answer

1.I come from Canada. Where .................you..................from?

a. do.............come         b. did ...... come     c. are ..........coming        d, have .....come

2. The telephones…………..by Alexander Graham Bell

A. is invented                 B. is inventing                C. Invented           D. was invented

3. The swimming pool .............. at 9 o’clock and ............ at 18.30 everyday.

a. opens............. closes   b. opens ...... closed      c. opened...... closed    d. opened......... closes

4. Three swimmers, Paul, Ed, and Jim, ................ now in competition  for medals.

a. is                       b. has been                      c. had been            d. are

5. Listen ! I .............. somebody knocking at the front door. 

a. am hearing         b. heard                          c. have heard         d. hear

6.. ………………………………………..yet?

A. Have the letters been typed            B. Have been the letters typed

C. Have the letters typed                    D. Had the letters typed

7. At 5 o’clock yesterday evening, I ……………my clothes.

a. am ironing         b. have ironed       c. ironed               d. was ironing.

8. I ………………..along the street when I suddenly heard footsteps behind me.

a. was walking      b. am walking        c. walk                            d. walked.

9. She ………….German for two years.

a. has learnt           b. is learning         c. learn        d. learns.

10. When  I last………..Jane, she ………..to find a job.

a. see/was trying    b. saw/was trying c. have seen/tried            d. saw/tried.

12. French is a…………language to learn than English is.

        A. difficult      B. more difficult       C. most difficult        D. more and more difficult

13. The more polluted air we breathe,…….we get.

          A. the more weaker                  B. the more weak

          C. the weaker                           D. weaker more

14. The more we study, the……we are.

          A. more good                 B. better               C. better than        D. good

15. The more I tried my best to help her, ……….she became.

          A. less lazy                     B. the lazier           C. the more lazy    D. lazier

16. The weather becomes………………

          A. colder with colder                                   B. colder and colder

          C. colder and more colder                            D. more and more cold

17. The more he slept,…………….irritable he became.

          A. the most                     B. the vey more     C. much more       D. the more

18. ………..he worked, the more he earned.

          A. The more hard           B. The hard           C. The harder        D. The hardest

19. ………I get to know Jim, the more I like him.

          A. For more                    B. More                C. The more D. The most

20. The competition makes the price of goods……….

          A. most cheap and cheap                    B. cheaper and cheaper

          C. more cheap and more cheap           D. cheaper and more cheaper

III. Rewrite:
1) Although Tom was a poor student, he studied very well.
=> In spite of ………………………………………………………
2) Mary could not go to school because she was sick.
 Because of ………………………………………………………………..
3) Although the weather was bad, she went to school on time.
=> Despite ……………………………………………………………..
4) My mother told me to go to school although my stomachache was sick.
=> In spite of ………………………………………………………………..
5) Because there was a big storm, I stayed at home.
=> Because of ……………………………………………………..
6) Tom was admitted to the university although his grades were bad.
 Despite …………………………………………………………………………
7) Although she has a physical handicap, she has become a successful woman.
=> Despite ……………………………………………………………………….
8) In spite of his good salary, Tom gave up his job.
=> Although………………………………………………………..

1
18 tháng 8 2021

II.

1. a

2. d

3. a

4. d

5. d

6. a

7. d

8. a

9. a

10. b

12. b
13. c

14. b

15. b

16. b

17. d

18. c

19. c

20. b

III.

1. In spite of being a poor student, Tom studied very well.

2. Because of her sickness, Mary could not go to school.

3. Despite the bad weather, she went to school on time.

4. In spite of my sick stomachache, my mother told me to go to school.

5. Because of the big storm, I stayed at home.

6. Despite his bad grades, Tom was admitted to the university.

7. Despite her physical handicap, she has become a successful woman.

8. Although his salary was good, Tom gave up his job.

18 tháng 8 2021

cảm ơn bạn nhiều ạ!!