8 How much do these apples cost?

9 THis is a blue car

11 Are there 40 classrooms in Phong's school?

13 How wide if the Great wall

mình lm ở dưới r mà bạn

We will have a three-month vacation

từ gợi ý hình như sai

theo mình câu 5 là :

We will have a three-month vacation.

Lỗi Sai :

We will have a three-month vacation.

lấy 25 / 60%=\(\dfrac{125}{3}\)m

Bài 2: 

Cả mảnh vải dài:

\(25:\dfrac{3}{5}=\dfrac{125}{3}\left(m\right)\)

1 C

2 D

3 D

4 D

5 C

6 D

7 C

8 D

9 C

10 B

n=231

a: Ta có: \(\dfrac{n\left(n+1\right)}{2}=231\)

\(\Leftrightarrow n^2+n-462=0\)

\(\Leftrightarrow n^2+22n-21n-462=0\)

\(\Leftrightarrow\left(n+22\right)\left(n-21\right)=0\)

\(\Leftrightarrow n=21\)

1 + 2 + 3 + 4 + ...... n = 231

n =

65 B

66 C

67 B

68 B

70 A

71 B

72 A

73 C

74 C

65b

66c

67b

68b

69a

70a

71b

72a

63a nhá

Câu 11:

Ta có: \(\left(2x-3\right)\left(3x+2\right)-\left(2x-3\right)^2=-18\)

\(\Leftrightarrow6x^2+4x-9x-6-4x^2+12x-9=-18\)

\(\Leftrightarrow2x^2+7x+3=0\)

\(\Leftrightarrow\left(x+3\right)\left(2x+1\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=-3\\x=-\dfrac{1}{2}\end{matrix}\right.\)

Câu nèo thé ?_?

Câu nào thế bạn????

where is câu hỏi???

will go

go

won't go

gets

will visit

get

will send

have

will lend

eat

will have

does

will arrive

don't do well

don't tell

will you 

calls

will be

will look