Xét tam giác ABC có G là trọng tâm 

=> AG=\(\frac{2}{3}\) AD, mà AD =12cm

=> GD=\(\frac{1}{3}\) AD

=> GD=\(\frac{1}{3}\) .12= 4cm

(3x-5)⁶-(3x-5)⁴=0

<=> (3x-5)⁴ [(3x-5)²-1]=0

<=> \(\orbr{\begin{cases}3x-5=0\\3x-5=\pm1\end{cases}}\)

<=>\(\orbr{\begin{cases}x=\frac{5}{3}\\x=2\end{cases}}\)hoặc x=\(\frac{4}{3}\)

Bác lấy góc đối của góc xOy rồi đo

-> đóng theo góc đó

-> xong

goi x;y;z lan luot la so hs cua 7A;7B;7C

Theo de ta co: \(\frac{x}{4}=\frac{y}{5}=\frac{z}{6}\)va x+y-z=60

Ap dung tinh chat..... ta dc

\(\frac{x}{4}=\frac{y}{5}=\frac{z}{6}=\frac{x+y-z}{4+5-6}=\frac{60}{3}=20\)

khi do \(\frac{x}{4}=20\Rightarrow x=80\)

           \(\frac{y}{5}=20\Rightarrow y=100\)

            \(\frac{z}{6}=20\Rightarrow z=120\)

Vay ......

ta co x y z tuong ung voi lop 7A 7B 7C 

theo de : \(\frac{x}{4}=\frac{y}{5}=\frac{z}{6}\)và x+y+z=60

ta theo tính chất dãy tỉ số bằng nhau

           \(\frac{x}{4}=\frac{y}{5}=\frac{z}{6}\)=\(\frac{x+y+z}{4+5+6}=\frac{60}{15}=4\)

\(\frac{x}{4}=4>x=16\)

\(\frac{y}{5}=4>y=20\)

\(\frac{z}{6}=4>z=24\)

vậy lop 7a co so hs la 16

lop 7b co so hs la 20 

lop 7c co so hs la 24

Hương vẽ tia ox' đối với tia ox và 

              vẽ tia oy' đối với tia oy 

Từ đó ta được góc x'oy' đối với góc xoy

Đo góc x'oy' bằng bao nhiêu là biết được góc xoy ( theo tính chất 2 góc đối nhau thì bằng nhau ) 

\(\left(2x-1\right)^2=\left(1-2x\right)^6\)

\(\left(2x-1\right)^2=\left(2x-1\right)^6\)

\(\left(2x-1\right)^6-\left(2x-1\right)^2=0\)

\(\left(2x-1\right)^2.\left[\left(2x-1\right)^4-1\right]=0\)

\(\Rightarrow\orbr{\begin{cases}\left(2x-1\right)^2=0\\\left(2x-1\right)^4-1=0\end{cases}\Leftrightarrow\orbr{\begin{cases}x=\frac{1}{2}\\x\in\left\{1;0\right\}\end{cases}}}\)

Vậy \(x\in\left\{\frac{1}{2};1;0\right\}\)

Tham khảo nhé~

1. She grows trees around her house.

-> Trees are grown around her house

2. She played a lot of games on the school ground yesterday.

-> A lot of games were played on the school ground yesterday 

3. They will built a house near the villa next year.

-> A house will be built near the villa next year

4. No one has eaten bread.

-> Bread hasn't been eaten

5. I can draw picture.

-> Picture can be drawn

6. She did her homework yesterday.

-> Her homework was done yesterday

7. I have learnt English for 6 years.

-> English has been learnt for 6 years

8. Her mother is washing some new clothes now.

-> Some new clothes are being washed by her mother now

9. Will some workers build my house in the future?

-> Will my house be built by some workers in the future?

10. He gives me many books.

-> Many books are given to me