Chị ơi ! OLM chặn gửi ảnh rùi

 lên gg

@LeBaoPhuong

đc có 1050k. lp 8 r, h đến mk lì xì ng ta chứ

có gần 6 sáu tr ah, lì xì mk ik cún

Mình sẽ tặng coin cho người làm đầu tiên nha

a) Áp dụng định lí Pytago vào ΔABC vuông tại A, ta được:

\(BC^2=AB^2+AC^2\)

\(\Leftrightarrow BC^2=3^2+4^2=25\)

hay BC=5(cm)

b) Xét ΔABC có AB<AC<BC(3cm<4cm<5cm)

mà góc đối diện với cạnh AB là \(\widehat{ACB}\)

và góc đối diện với cạnh AC là \(\widehat{ABC}\)

và góc đối diện với cạnh BC là \(\widehat{BAC}\)

nên \(\widehat{ACB}< \widehat{ABC}< \widehat{BAC}\)

Xét ΔABC có 

HB là hình chiếu của AB trên BC

HC là hình chiếu của AC trên BC

AB<AC

Do đó: HB<HC

c) Xét ΔCAB vuông tại A và ΔCAD vuông tại A có 

CA chung

AB=AD(gt)

Do đó: ΔCAB=ΔCAD(hai cạnh góc vuông)

Suy ra: CB=CD(hai cạnh tương ứng)

Xét ΔCBD có CB=CD(cmt)

nên ΔCBD cân tại C(Định nghĩa tam giác cân)

Số số hạng là:

\(\left(2x+3-1\right):2+1=x+2\left(số\right)\)

Theo đề, ta có: 

\(\dfrac{\left(2x+4\right)\left(x+2\right)}{2}=1260\)

\(\Leftrightarrow x^2+4x+4=1260\)

\(\Leftrightarrow x\in\varnothing\)

ĐỀ LUYỆN THI IOE LỚP 5

1. house / is / the city. / in / My

...............................................................................

2. Peter / go / on foot? / Does / to work

................................................................................

3. _ESULT

4. My mother gave me a _ _ _ _ _ _ _ yesterday.

5. We have English on Tuesday and Saturday. We have it ... a week.

A. once B. twice

C. two times D. three times

6. Go straight and Mai's house is ... your right.

A. at B. in
C. beside D. on

7. a shower / You should / take / twice / a week.

....................................................................................

8. an / orange. / is / That

..................................................

9. My father sometimes plays _ _ _ _ _ _ with his friends.

10. Remember to drink water everyday. It's good _ _ _ our health.

11. Choose the odd one:

A. sing B. play
C. draw D. yesterday

12. Make ... circles.

A. four B. a
C. for D. one

13. is / chicken. / favorite / My / food

.................................................................................

14. frogs / some / garden. / There are / in the

..................................................................................

15. I want to be a musician in _ _ _ future.

16. All of my friends watching cartoons _ _ TV.

17. She s going ... in the fall.

A. fish B. fishing
C. fishes D. to fish

18. Where is my cup of tea? – It's ... the kitchen.

A. in front of B. under
C. behind D. in

19. interesting / doing / We are / things. / many

...............................................................................

20. to school / I / usually / go / by bike.

................................................................................

21. Happy birthday to y_ _!

22. What subject are you good _ _ , Elisa?

23. I have ... on Monday. I the subject very much.

A. biology B. novel
C. education D. science

24. Choose the word that has the underlined part pronounced differently:

A. hour B. house
C. hen D. hot

25. to learn / many interesting things / I / about animals. / love

......................................................................................

26. usually / play / Trinh and Thang / table tennis / together.

.........................................................................................

27. We are having _ break now.

28. There are many cows in the _ _ _ _ _ _ _ of my family.

29. Hoa was very surprised when she looked at ... in the mirror.

A. she B. hers
C. herself D. her

30. Choose the word that has the underlined part pronounced differently from the others:

A. season B. weather
C. week D. beach

31. activities in / a lot of / interesting / There are / the festival.

.....................................................................................

32. has / and / a son. / a daughter / Mrs Hanh

.......................................................................................

33. Don't forget to post the letter _ _ _ me.

34. After dinner, my mother checks my homework b_ _ _ _ _ bedtime.

35. I ... born on November 17th.

A. was B. were

C. am D. is

ghi đáp án rồi thì xin làm gì