10) `sin2x+4(cosx-sinx)=4`

`<=>2sinxcosx+4(cosx-sinx)=4`

Đặt `t=cosx-sinx => sinxcosx=(1-t^2)/2 ( -\sqrt2 <= t <= \sqrt2)`

PT: `1-t^2 +4t=4`

`<=>` \(\left[{}\begin{matrix}t=3\left(L\right)\\t=1\left(TM\right)\end{matrix}\right.\)

`t=1 => cosx-sinx=1 <=>` \(\left[{}\begin{matrix}x=k2\pi\\x=-\dfrac{\pi}{2}+k2\pi\end{matrix}\right.\)

12) `2(cosx+sinx)=4sinxcosx+1`

Đặt `t=cosx+sinx => sinxcosx=(t^2-1)/2 (-\sqrt2 <=t <=\sqrt2)`

PT: `2t=2(t^2-1)+1`

`<=>t=(1\pm \sqrt3)/2` (TM)

Phần sau bạn tự làm nkaa, lười quá. =((((

Choose the correct answer to complete the sentence.

 This morning, I was _______ in a traffic jam and got to school fifteen minutes late. catch struck stuck block

Câu hỏi 13 (1 điểm) It is _______ to use a hand-held mobile phone while driving or riding.

 safe illegal important careful

Câu hỏi 14 (1 điểm) The film was so ________ that the two girls next to me couldn't stop crying.

exciting fascinating thrilling moving

Câu hỏi 15 (1 điểm) Critics were _________ at John Travolta in Pup Fiction. He was unexpectedly

incredible. disappointed worried surprised interested

Câu hỏi 16 (1 điểm) The ending of “American Psycho” is so _______. It left viewers with many questions. exhausting horrifying confusing moving

Câu hỏi 17 (1 điểm) James finds sci-fi movies really ________. He enjoys watching them.

fascinating embarrassing terrifying concerning

Câu hỏi 18 (1 điểm) Day of the Dead is celebrated ________ November 1st in Mexico.

duringin on at

Câu hỏi 19 (1 điểm) - Could I ask you a few questions about your favorite movies?

 - ___________.

But I don't want to I have no idea It's hard to say Sure. Go ahead

Câu hỏi 20 (1 điểm) My mother didn't _______ drink much coffee. But now she has become addicted to it.

be use to used to be used to

Câu hỏi 21 (1 điểm) There _________ a lot of trees in this court yard. They have all been cut down.

use to being use to be used to being used to be

Câu hỏi 22 (1 điểm) - How far is it from Vung Tau to Ho Chi Minh City? - ____________. It takes about two hours or more. You can get to Vung Tau by boat or bus. It's not too long It's about 120km

Câu hỏi 23 (1 điểm) _________, the hard rock Louder Than Life festival was cancelled. Despite the heavy rain After raining heavily Due to the heavy rain When it rain heavily

Câu hỏi 24 (1 điểm) - _________ do the Vietnamese decorate their houses during Tet? - During Tet, the Vietnamese decorate their houses with apricot or peach blossoms. WhenWhyWhichHow

Câu hỏi 25 (1 điểm) There is a special ________ for Japanese girls on March 3rd every year. celebrating celebrations celebrate celebration

Rewrite: thêm chủ ngữ (subject)

He/She/It eats rice.

1. do

2. preparation

3. taken

4. too

5. it

6. has

7. dangerous

8. keeping

9. example

10. enough

Missing subject.

1. beautiful

2. painful

3. powerful

4. fasten

5. wooden

6. national

7. cyclers

8. excited

9. comparison

10. performance

45. C
46. A
47. A
48. D
49. A
50. A

drivers

unpredictable

Chu vi là:

`(2+2)xx2 = 8 (cm)`

Đáp số: `8cm`.