EX1:

1. The match starts at three o'clock, so please be here by two.

2. The exhibition continues until 31 December. Don't miss it!

3. The train isn't leave at 10.15. It arrives at 10.15

4. What time do you have English class tomorrow?

5. Could you pick me up at the airport tomorrow morning? The plane lands at 8.30

6. Most supermarket in Spain aren't open until 10 a.m

7. What a terrible film!When it finishes?

8. The piano concert isn't begin at 8 o'clock. It is cancelled

9. There has been a change to the schedule and your flight now take off at 18.40

10. This summer holidays lasts for two months instead of three.

EX2.

1, B. derived

2, D. has had

Áp dụng tính chất dãy tỉ số bằng nhau, ta có:

\(\frac{a+b-c}{c}=\frac{b+c-a}{a}=\frac{a+c-b}{b}=\frac{a+b-c+b+c-a+a+c-b}{c+a+b}=\frac{a+b+c}{c+a+b}=1\)

Do đó: \(\frac{a+b-c}{c}=1\)\(\Rightarrow a+b-c=c\)\(\Rightarrow a+b+c=3c\)  (1)

\(\frac{b+c-a}{a}=1\)\(\Rightarrow b+c-a=a\)\(\Rightarrow b+c+a=3a\) (2)

\(\frac{a+c-b}{b}=1\)\(\Rightarrow a+c-b=b\)\(\Rightarrow a+c+b=3b\) (3)

Từ (1), (2), (3) \(\Rightarrow3a=3b=3c\)\(\Rightarrow a=b=c\)

Ta có: \(T=\left(10+\frac{b}{a}\right)\left(4+\frac{2c}{b}\right)\left(2017+\frac{3a}{c}\right)\)

\(=\left(10+\frac{a}{a}\right)\left(4+\frac{2c}{c}\right)\left(2017+\frac{3a}{a}\right)\)

\(=\left(10+1\right)\left(4+2\right)\left(2017+3\right)\)

\(=11.6.2020=133320\)

p/s: làm thế này đúng không ta, mình hong chắc lắm

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a,\(x^2+5xy+y^2=x^2+2.x.\frac{5}{2}y^2+\frac{25}{4}y^2-\frac{21}{4}y^2\)

\(=\left(x+\frac{5}{2}y\right)^2-\left(\frac{\sqrt{21}}{2}y\right)^2=\left(x+\frac{5}{2}y-\frac{\sqrt{21}}{2}y\right)\left(x+\frac{5}{2}y+\frac{\sqrt{21}}{2}y\right)\)

b,\(x^2-2x-11=y^2\)\(< =>\left(x-1\right)^2-y^2=12\)

\(< =>\left(x-y-1\right)\left(x-1+y\right)=12\)

tùy vô đk của x;y rồi xét các th

dat \(x^2=a\) ta co

\(4a^2-32a+1\)=\(4a^2-16a+6a\sqrt{7}+64-16x-24\sqrt{7}-6x\sqrt{7}+24\sqrt{7}-63\)=\(2a\left(2a-8+3\sqrt{7}\right)-8\left(2a-8+3\sqrt{7}\right)-3\sqrt{7}\left(2a-8+3\sqrt{7}\right)\)

=\(2a-8-3\sqrt{7}\left(2x-8+3\sqrt{7}\right)\)cuoi cung ban thay a=\(x^2\)vao la xong

có vẻ như nó rất xấu nhỉ

`4x^4 - 32x^2 + 1 = (2x^2)^2 - 2.2x^2 . 8 + 64 - 63 = (2x^2 - 8)^2 - 63`

\(=\left(2x^2-8\right)^2-63 =\left(2x^2-8\right)^2-\left(\sqrt{63}\right)^2=\left(2x^2-8-\sqrt{63}\right)\left(2x^2-8+\sqrt{63}\right)\)

ko nên vì nó ko trả lại cho mik đâu bạn ak

cái này thì liên quan gì đến ngữ văn 8 vậy ạ

Chào em, em tham khảo nhé!

1. We enjoy the peaceful atmosphere in the country. PEACE

2. The street doesn’t look attractive because it has a lot of rubbish. ATTRACT

3. Fish were died because of the oil spill. DIE

4. People in the south of my country speak the language with different accents. DIFFER

5. Are all types of pollution harmful to the health of humans and animals? HARM

6. The environmentalists are concerned about the oil spills in East Sea. ENVIRONMENT

7. Scotland is a legendary land and this is noted for its rich and interesting history. LEGEND

8. Many people in this area have cholera because they drink untreated water. TREAT

9. Niagara Falls, on the border of the USA and Canada, is one of the most spectacular sceneries in the world. SPECTACLE

10. The Sydney Opera House is an iconic monument of Australia. ICON

Chúc em học tốt và có những trải nghiệm tuyệt vời tại olm.vn!

Peaceful

attractive

dead

\(\frac{200}{x}+\frac{100}{x-10}-\frac{300}{x}=\frac{1}{2}\left(ĐKXĐ:x\ne0;10\right)\)

\(\Leftrightarrow\frac{100}{x-10}-\frac{100}{x}=\frac{1}{2}\Leftrightarrow\frac{100.2x}{2x\left(x-10\right)}-\frac{100.2\left(x-10\right)}{2x\left(x-10\right)}=\frac{x\left(x-10\right)}{2x\left(x-10\right)}\)

\(\Leftrightarrow\frac{200x-100.2\left(x-10\right)}{2x\left(x-10\right)}=\frac{x\left(x-10\right)}{2x\left(x-10\right)}\Rightarrow200x-200x+2000=x\left(x-10\right)\)

\(x\left(x-10\right)=2000\). Xét nghiệm tính được  \(x=50\left(tm\right)\)