Ta có :\(x^{20}=9.\left(x^2\right)^9\)

\(\Rightarrow x^{20}=9.x^{18}\)

Ta lại có: \(x^{20}=x^{18}.x^2=9.x^{18}\)

\(\Rightarrow x^2=9\)(x^18:x^`8 là =1 ko cần ghi)

\(\Rightarrow x=\sqrt{9}\)

\(\Rightarrow x=\)3 hoặc \(x=\)-3

Vậy: \(x=3;-3\)

Dãy có  tất cả số hạng là:(200,2-1,2):1 +1=200 số

Tổng dãy số là: (1,2+200,2)x200 :2=20140

Cmt đầu!

Choose ONE sentence that is closest in meaning with the original one
Câu 36. She last ate this kind of food in January.
A. She haven't eaten this kind of food since January.
B. She hasn't ate this kind of food for January.
C. She hasn't eaten this kind of food since January.
D. She hasn't eaten this kind of food in January.
Câu 37. What / you / plan / do / your / summer vacation?
A. What do you plan doing on your summer vacation?
B. What do you plan to do on your summer vacation?
C. What do you plan do on your summer vacation?
D. What you plan to do on your summer vacation?
Câu 38. You helped me. That was kind.
A. It was kind of you to help me.
B. It was kind of you helped me.
C. It was kind of you help me.
D. It was kind of you helping me.
Câu 39. This festival was first held in 1930.
A. They have first held this festival in 1930.
B. They would first hold this festival in 1930.
C. They first held this festival in 1930.
D. They first hold this festival in 1930.
Câu 40. "Have you ever been to My Son, Lan?", Hoa asked me.
A. Hoa asked me if I have been to My Son.
B. Hoa asked Lan if she has ever been to My Son.
C. Hoa asked Lan if she had ever been to My Son
D. Hoa asked me if I had ever been to My Son

Choose ONE sentence that is closest in meaning with the original one
Câu 36. She last ate this kind of food in January.
A. She haven't eaten this kind of food since January.
B. She hasn't ate this kind of food for January.
C. She hasn't eaten this kind of food since January.
D. She hasn't eaten this kind of food in January.
Câu 37. What / you / plan / do / your / summer vacation?
A. What do you plan doing on your summer vacation?
B. What do you plan to do on your summer vacation?
C. What do you plan do on your summer vacation?
D. What you plan to do on your summer vacation?
Câu 38. You helped me. That was kind.
A. It was kind of you to help me.
B. It was kind of you helped me.
C. It was kind of you help me.
D. It was kind of you helping me.
Câu 39. This festival was first held in 1930.
A. They have first held this festival in 1930.
B. They would first hold this festival in 1930.
C. They first held this festival in 1930.
D. They first hold this festival in 1930.
Câu 40. "Have you ever been to My Son, Lan?", Hoa asked me.
A. Hoa asked me if I have been to My Son.
B. Hoa asked Lan if she has ever been to My Son.
C. Hoa asked Lan if she had ever been to My Son
D. Hoa asked me if I had ever been to My Son

Gọi vận tốc của ca nô

       x " km/giờ " " x > 2 " 

Vận tốc của ca nô khi xuôi dòng là: 

      \(x+2\)km/giờ

Vận tốc của ca nô khi người dòng: 

      \(x-2\)km/giờ

Áp dụng công thức tính quãng đường 

      \(s=v\times t\)

Quãng đường AB :

     \("x+2"\times5\)km

Quãng đường BA :

     \("x-2"\times6\)km

Ta có 

     \("x+2"\times5="x-2"\times6\) " Vì quãng đường AB bằng Quãng đường BA "

Giải phương trình ta được :

       \(x=22\)

Vậy vận tốc của ca nô là 22 km/giờ

\(\Rightarrow\) Khoảng cách giữa hai bến A và B là :

                        \("22+2"\times5=120km\) 

                                                      Đáp số: 120 km

P/s: Thiệt là rối mắt quá đê

Lập Phương trình hơi rối mắt

Sao lại dùng dấu ngoặc kép

Lấy máy của Hằng mà dùng cho em dùng máy này nhá

\(\text{#3107.101107}\)

Ta có:

$12 = 3 \cdot 2^2$

$15 = 3 \cdot 5$

$18 = 3^2 \cdot 2$

$\Rightarrow$ ƯC`(12; 15; 18) = 3`

Vậy, ƯC`(12; 15; 18) = 3.`

12 = 2² x 3

15 = 3 x 5

18 = 2 x 3²

ƯCLN ( 12,15,18 ) = 2 x 3 = 6

ƯC ( 12,15,18 ) = Ư(6) = ( 1;2;3;6)

Tấm vải đỏ dài:

84:(3+4)x3 =36 m

Tấm vải xanh dài:

84-36=48m

Đáp số : Tấm vải đỏ:36m

Tấm vải xanh:48m

Học tốt trong mùa dịch nha!

Trl :

Bạn kia làm đúng rồi nhé !

Học tốt nhé bạn @

tớ rất cảm ơn bj Nguyễn Đức Minh Huy nhá 

THANKS cậu!!!!!!!!!!!!

có 1+2+3+*\(⋮\)9

6+*\(⋮\)9

=>*=3

thay vào ta có 

***.9=1233

***=137

Ta có:            \(\overline{abc}.9=123\overline{d}\left(d< 9\right)\) 

                      \(\Rightarrow123\overline{d}⋮9\)

                      \(\Rightarrow1+2+3+d⋮9\)

                      \(\Rightarrow6+d⋮9\)

                      \(\Rightarrow d=3\)

Với d=3, ta được:   \(\overline{abc}.9=1233\)

                               \(\Rightarrow\overline{abc}=1233:9=137\)

 ~~Học tốt nha~~

***.9=123*

***=123*  chia hết cho 9

==> 123* chia hết cho 9

==>(1+2+3+*) chia hết cho 9

==>(6+*) chia hết cho 9

Do đó *=3

Nên 123*=1233

Ta có ***.9=1233

***=1233:9

***=137