3 D

4 A

5 A

6 B

7 A

9 D

10 C

2 C

4 A

2 interesting 

Bài II, câu 3 chọn I 

4 - high

5 - ride

6 - put it on

7 - happy

9 - looking

10 - not to smoke

Bài III 

2 - C 

4 - A 

Áp dụng BĐT Bunhiacopxki cho 2 bộ số (\(\sqrt{a+b}\),\(\sqrt{b+c}\),\(\sqrt{a+c}\)) và (1,1,1) có: (1.\(\sqrt{a+b}\)+1.\(\sqrt{b+c}\)+1.\(\sqrt{a+c}\))² ≤ (a + b + b + c + c + a)(1² + 1² + 1²)

=> S² ≤ 2.3 = 6 ⇔ S ≤ \(\sqrt{6}\)

Dấu "=" xảy ra ⇔  \(\sqrt{a+b}\) = \(\sqrt{b+c}\) = \(\sqrt{a+c}\) ⇔ a +b = b + c = c + a

                                                                          ⇔ 1 - c = 1 - a = 1 - b

                                                                          ⇔ a = b = c = \(\dfrac{1}{3}\) 

Vậy maxS = \(\sqrt{6}\)  ⇔ a = b = c = \(\dfrac{1}{3}\) 

ta có ∠₁=70^o(hai góc đối đỉnh)

hai đường thẳng a và b cùng cắt c tạo thành 30^o+150^o=180^omà hai góc ở vị trí trong cùng phía

=>a//b(dấu hiệu)

=>∠₁=∠₂(hai góc đồng vị) ta lại có: ∠₁=70^o(cmt)=>∠₂=70^o

mà ∠₂=∠₃(hai góc đối đỉnh)=>∠₃=70^o

bài hơi khó hiểu(tại bạn không ghi rõ tên góc đó)

( 15-x ) + 2x = 2016-4

( 15-x ) + 2x = 2012

15-x + 2x = 2012

Vì - x + 2x = x nên có :

15 + x = 2012

x = 2012 - 15

x = 1997

(15-x)+2x=2016-2

(15-x)+2x=2012

15x1-Xx1=2012

1(15-x)=2012

15-x=2012:1

15-x=2012=>x=15-2012=-1997

Refer

1. “Your cousin speaks English very well” Paul told me

Paul said that ___________my cousin spoke English very well____________

2. “The man broke out of prison yesterday” said the policeman

The policeman told us_that the man had broken out of prison the day beforr__

3. “I’ll lend you this book as soon as I finish it” Owen said to me

Owen said __me that he would lend me that book as soon as he finished it___

4. “I think I forgot to turn off the lights this morning” Brenda told Brian

Brenda told Brian ____that he thought he had forgotten to turn off the lights that morning.____

5. “I work eight hours a day, except when the children are on holiday” said Mrs. Wood

Mrs. Wood said me that he worked eight hours a day, excepted when the children were on holiday

6. “You’ve been making good progress this semester” Miss Lynn told me

Miss Lynn said that _____I had been making good progress that semester_________

7. “If you bought all the tickets, you would win the lottery” the man said

The man told me ______that If I had bought all the tickets, I would win the lottery______________

8. “I like swimming but I don’t go very often” Jill said to Pam

Jill said that ______he liked swimming but he didn’t go very often___________________________

9. “I want to buy it, but I haven’t brought any money” said Patrick

Patrick told me _________that he wanted to buy it, but he hadn’t brought any money_______________________

10. “I’m going to visit my aunt in Hue, but I’m not sure when” said Mai

Mai told me _________that she was going to visit her aunt in Hue, but she was not sure when__________________

Bài 5:

a: AE là phân giác của góc BAC

=>\(\hat{BAE}=\hat{CAE}=\frac12\cdot\hat{BAC}\)

Xét ΔAEC có \(\hat{AEB}\) là góc ngoài tại đỉnh E

nên \(\hat{AEB}=\hat{EAC}+\hat{ECA}\)

\(=\frac12\cdot\hat{BAC}+\hat{ACB}=\frac12\left(180^0-\hat{ABC}-\hat{ACB}\right)+\hat{ACB}=90^0-\frac12\cdot\hat{ACB}-\frac12\cdot\hat{ABC}+\hat{ACB}\)

\(=90^0-\frac12\cdot\hat{ABC}+\frac12\cdot\hat{ACB}=90^0-\frac12\left(\hat{ABC}-\hat{ACB}\right)\)

b: BK//AE
=>\(\hat{ABK}=\hat{BAE}\) (hai góc so le trong) và \(\hat{AKB}=\hat{EAC}\) (hai góc đồng vị)

mà \(\hat{BAE}=\hat{EAC}\) (AE là phân giác của góc BAC)

nên \(\hat{ABK}=\hat{AKB}\)

=>ΔABK có hai góc bằng nhau

Bài 6:

a: AM//BD

=>\(\hat{BMA}=\hat{CBD}\) (hai góc đồng vị) và \(\hat{BAM}=\hat{ABD}\) (hai góc so le trong)

mà \(\hat{CBD}=\hat{ABD}\) (BD là phân giác của góc ABC)

nên \(\hat{BMA}=\hat{BAM}\)

b: ΔBAM có \(\hat{BAM}=\hat{BMA}\)

nên ΔBAM cân tại B

ΔBAM cân tại B

mà BI là đường phân giác

nên BI⊥AM

a: 4/25=16/100

-7/4=-175/100

9/50=18/100

b: -7/10=-28/40

11/20=22/40

-10/40=-10/40

c: 5/18=10/36

7/12=21/36

11/6=66/36