\(3\sqrt{x}-2x=0\)

\(\Leftrightarrow3\sqrt{x}=2x\)

\(\Leftrightarrow\sqrt{x}=\frac{2x}{3}\)

\(\Leftrightarrow\left(\sqrt{x}\right)^2=\frac{4x^2}{9}\)

\(\Leftrightarrow x=\frac{4x^2}{9}\)

\(\Leftrightarrow\frac{4x^2}{x}=9\)

\(\Leftrightarrow4x=9\)

\(\Leftrightarrow x=\frac{9}{4}\)

\(3\sqrt{x}-2x=0\)

\(\Leftrightarrow9x-4x^2=0\)

\(\Leftrightarrow x\left(9-4x\right)=0\)

\(\Leftrightarrow\orbr{\begin{cases}x=0\\9-4x=0\end{cases}\Leftrightarrow\orbr{\begin{cases}x=0\\x=\frac{9}{4}\end{cases}}}\)

Các bạn giúp mk làm 5 bài này nhé. mk đang cần gấp. Thanks các bạn nhiều

Mk cần gấp 5 bài này trong hôm nay. Các bạn cố gắng giúp mk. Thanks

oke bạn

Bài 7

Cửa hàng có 60 xe máy.

• Buổi sáng bán được:
  \(\frac{3}{20} \times 60 = 9\) (xe)

→ Còn lại: \(60 - 9 = 51\) (xe)

• Buổi chiều bán được:
  \(\frac{4}{17} \times 51 = 12\) (xe)

→ Sau hai buổi còn lại:
\(51 - 12 = 39\) (xe)

✅ Đáp số: 39 xe máy

Bài 8

• Lần 1: vòi chảy được \(\frac{1}{2}\) bể
• Lần 2: vòi chảy được \(\frac{2}{5}\) bể

Tổng nước đã chảy:

\(\frac{1}{2} + \frac{2}{5} = \frac{5}{10} + \frac{4}{10} = \frac{9}{10} \&\text{nbsp};\text{b}ể\)

Phần còn thiếu:

\(1 - \frac{9}{10} = \frac{1}{10} \&\text{nbsp};\text{b}ể\)

Phần này tương ứng 1000 lít, nên:

\(\frac{1}{10} \&\text{nbsp};\text{b}ể\&\text{nbsp}; = 1000 \&\text{nbsp};\text{l} \overset{ˊ}{\imath} \text{t}\)

→ Cả bể chứa:

\(1000 \times 10 = 10 \textrm{ } 000 \&\text{nbsp};\text{l} \overset{ˊ}{\imath} \text{t}\)

✅ Đáp số: 10 000 lít

Bài 9

Giá sách: 4000 đồng

Giảm:

\(\frac{1}{5} \times 4000 = 800 \&\text{nbsp};đ \overset{ˋ}{\hat{\text{o}}} \text{ng}\)

Số tiền phải trả:

\(4000 - 800 = 3200 \&\text{nbsp};đ \overset{ˋ}{\hat{\text{o}}} \text{ng}\)

✅ Đáp số: 3200 đồng

Bài 10

Hình chữ nhật có:

• Chiều dài: \(\frac{7}{8}\) m
• Chiều rộng: \(\frac{5}{21}\) m

Nửa chu vi:

\(\frac{7}{8} + \frac{5}{21}\)

Quy đồng:

\(\frac{7}{8} = \frac{147}{168} , \frac{5}{21} = \frac{40}{168}\)

Cộng:

\(\frac{147}{168} + \frac{40}{168} = \frac{187}{168}\)

Phân số đã tối giản.

✅ Đáp số: \(\frac{187}{168}\) m

hình bé quá

sin 65⁰=cos 35⁰
\(cos70^0=sin30^0\)
\(tan80^0=cot20^0\)
\(cot68^0=tan32^0\)

1 create $\rightarrow$ c. energy (tạo ra năng lượng)

2 drive $\rightarrow$ a. machinery (vận hành máy móc)

3 generate $\rightarrow$ e. electricity (phát/tạo ra điện)

4 turn $\rightarrow$ b. turbines (quay tua-bin)

5 heat $\rightarrow$ d. houses (sưởi ấm nhà cửa)

b

1 How many types of energy sources are mentioned in the text? What are they?
$\rightarrow$ Two types of energy sources are mentioned. They are renewable and non-renewable energy sources. (hoặc kể tên cụ thể: fossil fuels/coal/oil, hydro power, nuclear power, wind power, solar power)

2 What are the disadvantages of hydro and nuclear power?
$\rightarrow$ Hydro power is expensive to build dams, and nuclear power can be very dangerous.

3 Why do you think the wind and the sun are called alternative sources of energy?
$\rightarrow$ Because they are clean, renewable, and can be used instead of non-renewable sources (fossil fuels).

4 What types of energy does Viet Nam use most?
$\rightarrow$ Viet Nam uses hydro power and fossil fuels (coal, gas, oil) most.

5 What does the professor think Viet Nam will use more in the future?
$\rightarrow$ He thinks Viet Nam will use more renewable energy sources like solar and wind power in the future.

Me: What are you doing on Sunday afternoon?

Friend: I’m not doing anything. / Nothing much.

Me: Do you want to see a movie with me?

Friend: Sure. What movie is it?

Me: It's "The Journey to Mars".

Friend: What time does it start?

Me: It starts at 4 p.m.

Friend: Great! See you then.

Me: What are you doing on Saturday morning?

Friend: I’m free.

Me: Would you like to go to the movies with me?

Friend: Sounds good. What movie do you want to watch?

Me: How about "The Forest Book"?

Friend: What time is it on?

Me: It's at 10 a.m.

Friend: OK, let's meet at the cinema at 9:45.