Tìm x, biết:

a) \(\dfrac{x}{3}\) - 5 = \(\dfrac{2x}{5}\)

b) 4 + 3x = 8 - x

c) 2 . 3\(^{x+1}\) - 5 . 3\(^x\) = 243

III. Read and choose True, False or Not given

Earth Day is a day that is intended awareness and appreciation for the Earth's natural environment. On April 22nd,1970,people all over the country made promises to help the environment -  and the tradition continues. Aprill 22nd,2012 marks the 42nd anniversary of the first Earth Day. Earth Day is now coordinated globally by the Earth Day Network, and is celebrated in more than 175 countries every year.
There are so many ways to celebrate the Earth Day, but many like to take that extra step and do a little something more for the Earth on the Earth Day of this year by planting a tree or participating in a community cleanup event.Planting trees helps to reduce greenhouse gas emissions, cleans pollutions, secures soil in place to prevent erosion, and provides homes for a lot of biodiversity.
People also can save the Earth everyday by recycling, starting a compost pile, taking public transportation, carpool, replacing light bulbs with energy efficient bulbs, donating old electronics instead of throwing them away and having a garage sale.
1.The first Earth Day was celebrated n 1970,
2. The fist country to celebrate Earth Day is England.
3. The Earth Day of 2012 is the twenty fourth Earth Day.
4. We has better us energy efficient bulbs.

Tính nhanh:

a) A = 2\(^{2010}\) - 2\(^{2009}\) - 2\(^{2008}\) - 2\(^{2007}\) - ... - 2 - 1

b) B = 20 . 8 - 33 . 64 + 17 . 8 + 9 . 16 . 8 - 11 . 128

c) C = ( \(\dfrac{1}{1.2.3}\) + \(\dfrac{1}{2.3.4}\) + ... + \(\dfrac{1}{2009.2010.2011}\) ) . \(\dfrac{2010.2011}{1010.527}\)

Cảm nghĩ về đoạn thơ sau:

" Trái con như thách thức

Trăm thứ giặc, thứ sâu

Thách kẻ thù sự sống

Phá đời không dễ đâu!

Chao! Cái quả sấu non

Chưa ăn mà đã giòn

Nó lớn như trời vậy

Và sẽ thành ngọt ngon.

(Quả sấu non trên cao - Xuân Diệu)

6. She sings______.

A beautiful B. nice C. beautifully D. lovely

7. Everybody wished_____this activity.

A. keep B. to keep. C. keeping D. to keeping

8 He volunteered______us all in his car.

A take B. to take C. taking D. to taking

9. We can learn more about the undersea world____thisinvention.

A. because B. for C. thanks to D. thanks for

10. The number of participants____every week.

A. increase B. increases C. is increase D. are increase

Exercise 2. Rewrite the following sentences using conditional sentence type 1 

1. Drive carefully or you will cause accident.

=> If you drive to fast, you may have an accident

2. Be quiet or you’ll wake the baby up

=> If you don’t keep silent, you’ll wake the baby up.

3. I don’t have free time, that’s why I can’t go to see him.

=> If I had free time, I would go to see him