a) ĐKXĐ:

x³ - 1 khác 0

x khác 1

b) A = (5x² + 5x + 5)/(x³ - 1)

= 5(x² + x + 1)/[(x - 1)(x² + x + 1)]

= 5/(x - 1)

Thay x = 7 vào A, ta được:

A = 5/(7 - 1)

= 5/6

4/ Chứng minh rằng :a.     76 +75 – 74 chia hết cho 11 . bạn nào giúp mình với (giải thích cho mình hiểu luôn nha các bạ... - Hoc24

\(7^6+7^5-7^4\)

\(=7^4\left(7^2+7-1\right)\)

\(=7^4\cdot55⋮11\)

\(\frac{16}{45}>\frac{16}{64}=\frac{1}{4}=\frac{100}{400}>\frac{99}{400}\) 

nên:\(\frac{16}{45}>\frac{99}{400}\)

\(\frac{16}{45}>\frac{16}{64}=\frac{1}{4}=\frac{100}{400}>\frac{99}{400}\Rightarrow\frac{16}{45}>\frac{99}{400}\)

Bài tập về nhà thì bạn tự là đi

14 Lan asked Thu where she could find the new cartoons

15 Phong asked Lan if their teacher asked them to clean up the room

16 She asked me to give her some money

17 Tam asked Thu if she would be there for five days

18 The students asked their teacher to give them easier homework

19 She asked her husban if they needed some help

20 Lan asked Hoa is she might have a look at her picture

21 Lam asked Lan if their class would take part in that competition

42 rains

43 gives

44 returns

45 will go

46 study

47 would try

48 has just published

49 has traveled

50 wouldn't lose/didn't lose/hadn't lost

51 didn't rain

52 hot

53 Have you ever been - have been

54 could

55 wants - study

56 listening

57 rings

58 took part

59 was spoken

60 do - to learn

I

0 C

1 D

2 C

3 A

II

0 C

1 C

2 D

III

0 C

1 D

2 B

3 B

4 D

5 C

6 B

7 A

8 C 

I

1 C

2 D

3 D

4 A

5 B

II

6 C

7 A

8 A

9 A

10 D

11 C

12 C

13 C

14 D

15 D

16 D

17 C

18 B

19 C

20 B

III

21 painting => being painted

22 she => bỏ

23 doesn't => isn't

24 at => in

25 didn't => wouldn't

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