Tham khảo

1. Someone will clean the room today. =>THE ROOM WILL BE CLEANED TODAY

2. Someone might steal the car. =>THE CAR MIGHT BE STOLEN

3. They had to cut down that tree.=>THAT TREE HAD TO BE CUT DOWN

4. They're going to demolish the old houses.=>THE OLD HOUSES ARE GOING TO BE DEMOLISHED

5. We can't restore the picture. =>THE PICTURE CAN'T BE RESTORED

6. You must make an appointment in advance.=>AN APPOINTMENT MUST BE MADE IN ADVANCE

7. I don't want people to make me a fool. =>I DON'T WANT TO BE MADE A FOOL

8. Someone has to look after the garden.=>THE GARDEN HAS TO BE LOOKED AFTER

9. He wants everybody to serve him. =>HE WANTS TO BE SERVED

10. They're going to interview him next week=>HE IS GOING TO BE INTERVIEWED NEXT WEEK

7 Tim told me if I didn't have a degree, I couldn't get a job easily

8 I told Martin he could sleep well at night, if he didn't drink too much coffee

9 Jim told Daise unless she chooses the words more carefully, she would be introuble

10 I said to Dick I would forget Ann's birthday if he didn't remind me

11 Jim told Jane he wouldn't have been late for his intervire if he hadn't missed the train

12 I told my friends if it didn't rain that morning, we could go for a picnic

13 I said if Linda had been at home the day before, I could have visited her

14 They said if the weather were nice that day, they would go to the zoo

15 They said they would go to the beach if the weather was nice the day after (loại 1)

16 I told Mike Halen would know what to do if she were late (2)

17 Mark said he would have spoken to Frank if he had seen him the day before (3)

18 The girl said he wouldn't run away if she saw a spider (2)

19 David told her if she had too much to do, she could ask him to help her (2)

20 He told me if I studied harder, I would get high marks in next exam (1)

Tham khảo

1. Someone will clean the room today. =>THE ROOM WILL BE CLEANED TODAY

2. Someone might steal the car. =>THE CAR MIGHT BE STOLEN

3. They had to cut down that tree.=>THAT TREE HAD TO BE CUT DOWN

4. They're going to demolish the old houses.=>THE OLD HOUSES ARE GOING TO BE DEMOLISHED

5. We can't restore the picture. =>THE PICTURE CAN'T BE RESTORED

6. You must make an appointment in advance.=>AN APPOINTMENT MUST BE MADE IN ADVANCE

7. I don't want people to make me a fool. =>I DON'T WANT TO BE MADE A FOOL

8. Someone has to look after the garden.=>THE GARDEN HAS TO BE LOOKED AFTER

9. He wants everybody to serve him. =>HE WANTS TO BE SERVED

10. They're going to interview him next week=>HE IS GOING TO BE INTERVIEWED NEXT WEEK

ok nha

A = 1/2 + 1/6 + 1/16 + ... + 1/4084441   có : 2021 - 1 + 1 = 2021 số

1 = 1/2021 + 1/2021 + ... + 1/2021   có 2021 số 

vậy 1 > A

a.theo em thì mai ko giữ lời hứa,tuy nhiên mai ko sai vì phải lên họp gấp

b.e nghĩ rằng,vc đổ lỗi cho mai là sai vì các bạn đã quá chủ quan ko tự dò lại bài.tuy ko có bạn dò bài thì ta vẫn nên tự dò lại như thế vừa giúp ta thuộc bài lại rèn cho ta tính tự giác cho bản thân

Bài IV:

1: Xét tứ giác MAOB có

\(\widehat{MAO}+\widehat{MBO}=90^0+90^0=180^0\)

=>MAOB là tứ giác nội tiếp

=>M,A,O,B cùng thuộc một đường tròn

2: Xét (O) có

MA,MB là các tiếp tuyến
Do đó: MA=MB

=>M nằm trên đường trung trực của AB(1)

Ta có: OA=OB

=>O nằm trên đường trung trực của AB(2)

Từ (1) và (2) suy ra MO là đường trung trực của BA

=>MO\(\perp\)AB tại H và H là trung điểm của AB

Xét ΔMAO vuông tại A có AH là đường cao

nên \(MH\cdot MO=MA^2\left(3\right)\)

Xét (O) có

ΔACD nội tiếp

AD là đường kính

Do đó: ΔACD vuông tại C

=>AC\(\perp\)CD tại C

=>AC\(\perp\)DM tại C

Xét ΔADM vuông tại A có AC là đường cao

nên \(MC\cdot MD=MA^2\left(4\right)\)

Từ (3) và (4) suy ra \(MA^2=MH\cdot MO=MC\cdot MD\)

3: Ta có: \(\widehat{MAI}+\widehat{OAI}=\widehat{OAM}=90^0\)

\(\widehat{HAI}+\widehat{OIA}=90^0\)(ΔAHI vuông tại H)

mà \(\widehat{OAI}=\widehat{OIA}\)

nên \(\widehat{MAI}=\widehat{HAI}\)

=>AI là phân giác của góc HAM

Xét ΔAHM có AI là phân giác

nên \(\dfrac{HI}{IM}=\dfrac{AH}{AM}\left(5\right)\)

Xét ΔOHA vuông tại H và ΔOAM vuông tại A có 

\(\widehat{HOA}\) chung

Do đó: ΔOHA đồng dạng với ΔOAM

=>\(\dfrac{OH}{OA}=\dfrac{HA}{AM}\)

=>\(\dfrac{OH}{OI}=\dfrac{AH}{AM}\left(6\right)\)

Từ (5) và (6) suy ra \(\dfrac{OH}{OI}=\dfrac{IH}{IM}\)

=>\(HO\cdot IM=IO\cdot IH\)

Bài 4:

\(a,\Rightarrow5⋮x\Rightarrow x\inƯ\left(5\right)=\left\{1;5\right\}\\ b,\Rightarrow x-2+7⋮x-2\\ \Rightarrow x-2\inƯ\left(7\right)=\left\{1;7\right\}\\ \Rightarrow x\in\left\{3;9\right\}\\ c,\Rightarrow3\left(x+1\right)+4⋮x+1\\ \Rightarrow x+1\inƯ\left(4\right)=\left\{1;2;4\right\}\\ \Rightarrow x\in\left\{0;1;3\right\}\\ d,\Rightarrow10x+6⋮2x-1\\ \Rightarrow5\left(2x-1\right)+11⋮2x-1\\ \Rightarrow2x-1\inƯ\left(11\right)=\left\{1;11\right\}\\ \Rightarrow x\in\left\{1;6\right\}\\ e,\Rightarrow x\left(x+3\right)+11⋮x+3\\ \Rightarrow x+3\inƯ\left(11\right)=\left\{1;11\right\}\\ \Rightarrow x=8\left(x\in N\right)\\ f,\Rightarrow x\left(x+3\right)+2\left(x+3\right)+5⋮x+3\\ \Rightarrow x+3\inƯ\left(5\right)=\left\{1;5\right\}\\ \Rightarrow x=2\left(x\in N\right)\)