\(\left[\left(6x-72\right):2-84\right].28=5628\)\(\Rightarrow\left(6x-72\right):2-84=5628:28=201\)

\(\Rightarrow\left(6x-72\right):2=201+84=285\)

\(\Rightarrow6x-72=285.2=570\)

\(\Rightarrow6x=570+72=642\)

\(\Rightarrow x=\frac{642}{6}=107\)

[(6x-72):2-84].28=5628

[(6x-72):2-84] =5628:28

[(6x-72):2-84] =201

[(6x-72):2] =201+84

[(6x-72):2] =285

6x-72 =285.2

6x-72 =570

6x =570+72

6x =642

x =642:6

x =107

mình làm vắng tắt.

6x = 5628/28 + 84 * 2 +72

6x = 642

x = 642/6 = 107

`(x-2)^2/12-(x+1)^2/21=[(x-4)(x-6)]/28`

`<=> [7(x^2-4x+4)]/84-[4(x^2+2x+1)]/84=[3(x^2-6x-4x+24)]/84`

`=>7x^2 -28x+28 - 4x^2 -8x-4 = 3x^2- 18x -12x +72`

`<=> 7x^2 -28x -4x^2 -8x +18x +12x -3x^2 =72-28+4`

`<=>-6x = 48

`<=> x = -8`

Vậy `S={-8}`

 \(\dfrac{\left(X-2\right)^2}{12}\)- \(\dfrac{\left(X+1\right)^2}{21}\)=\(\dfrac{\left(X-4\right)\left(X+6\right)}{28}\)

<=> \(\dfrac{7\left(X-2\right)^2}{84}\)-\(\dfrac{4\left(X+1\right)^2}{84}\)=\(\dfrac{3\left(X-4\right)\left(X-6\right)}{84}\)

<=>7(x-2)² - 4(x+1)² = 3(x-4)(x-6)

<=>7(x² - 4x + 4) - 4(x² + 2x + 1) = 3(x² - 10x + 24)

<=>7x² - 28x + 28 - 4x² - 8x - 4 = 3x² -30x +72

<=>7x² - 4x² - 3x² - 28x - 8x + 30x = - 28 + 4 + 72

<=> 50x = 48

<=> x = \(\dfrac{48}{50}\)

<=> x = \(\dfrac{24}{25}\)

S = \(\left\{\dfrac{24}{25}\right\}\)

\(\dfrac{8\times3\times4}{16\times3}\)

\(=\dfrac{8\times3\times2\times2}{8\times2\times3}\)

b) \(\dfrac{30\times25\times7\times8}{75\times8\times12\times14}\)

a) \(\dfrac{5}{3};\dfrac{29}{14}\)

b) \(\dfrac{9}{21};\dfrac{45}{105}\)

a) \(\dfrac{5}{3}\);\(\dfrac{99}{100}\);\(\dfrac{29}{14}\)

b) \(\dfrac{9}{21}\);\(\dfrac{33}{77}\);\(\dfrac{45}{105}\)

Our Greener Would will able to have a clean air. It has many green trees around the Earth. Air around the world will not be able to pollute the air. People will not be affected by breathing. So, I love it so much.

Hơi ngắn

Our green world will be able to have a clean air. It has many green trees around the Earth. Air around the world will not be able to pollute the air. People will not be affected by breathing. So, I love it so much.

\(\dfrac{2^8\cdot9^3}{6^4\cdot4^3}=\dfrac{2^8\cdot3^6}{2^4\cdot3^4\cdot2^6}=\dfrac{2^8\cdot3^6}{2^{10}\cdot3^4}=\dfrac{3^2}{2^2}=\dfrac{9}{4}\)

\(12^5\div\left(2^6\cdot3^8\right)=2^{10}\cdot3^5\div\left(2^6\cdot3^8\right)=\dfrac{2^{10}\cdot3^5}{2^6\cdot3^8}=\dfrac{2^4}{3^3}=\dfrac{16}{27}\)

\(\dfrac{3^{12}\cdot2^{14}\cdot5^5}{10^5\cdot6^8\cdot12^4}=\)\(\dfrac{3^{12}\cdot2^{14}\cdot5^5}{5^5\cdot2^5\cdot2^8\cdot3^8\cdot2^8\cdot3^4}=\)\(\dfrac{3^{12}\cdot2^{14}\cdot5^5}{5^5\cdot2^{21}\cdot3^{12}}=\dfrac{1}{2^7}=\dfrac{1}{128}\)

1) \(\dfrac{2^8\cdot9^3}{6^4\cdot4^3}=\dfrac{2^8\cdot3^6}{2^4\cdot2^6\cdot3^4}=\dfrac{3^2}{2^2}=\dfrac{9}{4}\)

2) \(12^5:\left(2^6\cdot3^8\right)=\dfrac{2^{10}\cdot3^5}{2^6\cdot3^8}=\dfrac{2^4}{3^3}=\dfrac{16}{27}\)

\(\dfrac{3^{12}\cdot2^{14}\cdot5^5}{10^5\cdot6^8\cdot12^4}=\dfrac{3^{12}\cdot2^{14}\cdot5^5}{5^5\cdot2^{21}\cdot3^{12}}=\dfrac{1}{128}\)

PHAN I : ( 5 diem )

Doc doan van va thuc hien yeu cau neu o ben duoi :

'' Bong tre trum len au yem lang , ban , xom , thon . Duoi bong tre cua ngan xua , thap thoang mai dinh mai chua co kinh . Duoi bong tre xanh , ta gin giu mot nen van hoa lau doi . Duoi bong tre xanh , da tu lau doi , nguoi dan cay Viet Nam dung nha , dung cua , vo ruong , khai hoang . Tre an o voi nguoi doi doi , kiep kiep . Tre , nua , mai ,vau giup nguoi tram cong nghin viec khac nhau ''

Cau 1: Doan van tren trich trong van ban nao ? Ai la tac gia ? Van ban do thuoc the loai gi ?

Cau 2 : Xac dinh chu ngu , vi ngu trong cau sau :

Duoi bong tre cua ngan xua , thap thoang mai dinh mai chua co kinh

Cau 3 : Hay xac dinh va neu tac dung cua bien phap tu tu duoc su dung trong cau van : Tre an o voi nguoi doi doi , kiep kiep

Cau 4 : Bang hieu biet ve van ban co doan trich tren , hay ghi lai cam nhan cua em ve su gan bo cua cay tre voi con nguoi Viet Nam bang mot doan van khoang 5 cau . Trong doan van co su dung mot cau tran thuat don co tu '' la '' ( gach chan , chu thich ro )

5x+47y :17

5x+30y+17y :17

Suy ra 5x+30y : 17

5(x+6y) :17

Mà UCLN ( 5;17)=1

Suy ra x+6y là B(17)

Although we won the Oscar to his film, he didn't feel happy (Despite)

=>Despite winning the Oscar to his film, he didn't feel happy.

Although we won the Oscar to his film, he didn't feel happy (Despite)

=>Despite the fact that we won the Oscar to his film, he didn't feel happy