1. Ann is very friendly. She lives next door.

Ann who lives next door is very friendly

2. The man is a famous actor. You met him at the party last night.

The man whom you met at the party last night is a famous actor

3. There are some words. They are very difficult to translate.

There are some words which are very difficult to translate

4. The sun provides us with heat and light. It is one of millions of stars in the universe.

The sun, which is one of millions of stars in the universe, provides us with heat and light

5. Students will be punished. Their homework is late.

 Students who homework is late will be punished

6. I was looking for a book this morning. I've found it now.

I've found the book I was looking for this morning

7. Is that the car? You want to buy it.

  Is that the car which you want to buy ?

8. Sandra works in advertising. You were talking to her.

Sandra, who you were talking to, works in advertising.

9. Lake Prespa is a lonely beautiful lake. It‟s on the north Greek border.

Lake Prespa, which is a lonely beautiful lake, is on the north Greek border

10. The little girl ate sweets the whole way. She sat next to me on the coach.

The little girl who sat next to me on the coach ate candy the whole way

1. Ann, who lives next door, is very friendly.

2. The man who/that you met at the party last night is a famous actor.

3. There are some words that/which are very difficult to translate.

4. The sun, which is one of millions of stars in the universe, provides us with heat and light.

5. Students whose homework is late will be punished.

6. I've found the book that/which I was looking for in the morning.

7. Is that the car that/which you want to buy?

8. Sandra, who you were talking to, works in advertising.

9. Lake Prespa, which is on the north Greek border, is a lonely beautiful lake.

10. The little girl who/that sat next to me on the coach ate sweets the whole way.

A B C D 4 9 E I

a, Xét tam giác ABD và tam giác BDC ta có : 

^BAD = ^CBD ( gt )

^ABD = ^BDC ( so le trong )

Vậy tam giác ABD ~ tam giác BDC ( g.g )

\(\Rightarrow\frac{AB}{BD}=\frac{BD}{DC}\)( tỉ số đồng dạng ) \(\Rightarrow BD^2=AB.DC=4.9=36\)

\(\Rightarrow BD=\sqrt{36}=6\)cm 

b, Gọi giao điểm AC và BD là I

Xét tam giác BIE và tam giác AID có : BE // AD 

Theo hệ quả Ta lét ta có : \(\frac{BI}{ID}=\frac{IE}{IA}=\frac{BE}{AD}\)

Xét tam giác AIB và tam giác DIC có AB // CD ( ABCD là hình thang )

\(\frac{AI}{IC}=\frac{IB}{ID}=\frac{AB}{DC}\)

mà \(\frac{BE}{AC}=\frac{AB}{DC}=\frac{IB}{ID}\Rightarrow BE.DC=AB.AC\)

M N P 3 4 H D K

a, Xét tam giác NMP vuông tại M, có đường cao MH 

Áp dụng định lí Py ta go ta có : 

\(NP^2=MN^2+MP^2=9+16=25\Rightarrow NP=5\)cm 

Vì ND là đường phân giác nên : \(\frac{MN}{NP}=\frac{MD}{DP}\)mà \(DP=MP-MD=4-MD\)

hay \(\frac{3}{5}=\frac{MD}{4-MD}\Rightarrow12-3MD=5MD\)

\(\Leftrightarrow8MD=12\Leftrightarrow MD=\frac{12}{8}=\frac{3}{2}\)cm 

b, Xét tam giác MHN và tam giác MNP ta có :

^NHM = ^NMP = 90⁰

^N _ chung 

Vậy tam giác MHN ~ tam giác MNP ( g.g )

c, Xét tam giác NDM và tam giác NKH ta cs : 

^MNP = ^NHK = 90⁰

\(\frac{MN}{NH}=\frac{MK}{KH}\)( NK là đường phân giác )

Vậy tam giác NDM ~ tam giác NKH ( c.g.c )

\(\Rightarrow\frac{ND}{NK}=\frac{NM}{NH}\)( tỉ số đồng dạng ) \(\Rightarrow ND.NH=NM.NK\)

Ngày sau bán được số phần là:

\(\frac{1}{3}\cdot\frac{3}{4}\)=\(\frac{1}{4}\)(số gạo)

Số gạo còn lại tương ứng với số phần là:

\(1-\frac{1}{3}\)\(-\frac{1}{4}\)\(=\frac{5}{12}\)(số gạo)

Lúc đầu cửa hàng có số tạ gạo là:

\(15:\frac{5}{12}=36\)(tạ gạo)

                   Đáp số:\(36\)tạ gạo.

36 tạ gạo nha

a, Đặt \(x=3k;y=5k\)

hay \(A=\frac{5.9k^2+3.25k^2}{10.9k^2-3.25k^2}=\frac{45k^2+75k^2}{90k^2-75k^2}=\frac{120k^2}{15k^2}=\frac{120}{15}=8\)

b, Ta có : \(x-y-z=0\Rightarrow x-y=z;x-z=y;x=y+z\)

\(B=\left(1-\frac{z}{x}\right)\left(1-\frac{x}{y}\right)\left(1+\frac{y}{z}\right)\)

\(=\frac{x-z}{x}.\frac{y-x}{y}.\frac{z+y}{z}\)

hay \(\frac{y+z-z}{x}.\frac{x-z-x}{y}.\frac{x-y+y}{z}=\frac{y\left(-z\right).x}{xyz}=-1\)

bởi vì 1 người làm mất 24 ngày  ta lấy 24:6 =4 người rồi ta lấy 4 người +4nguowif = 8 người

8 chuan luon

ABC=2

Đề kiểm tra của mình nè

1.They are interseting in the film which they found.

2.Despite being old,she works hard.

3.We used to cycle to school two years ago.

4, Although he set off early,he arrived late.

Bai 1 ; Viet lai cau sao cho nghia khong doi 

1, They found the film intererting 

⇒THEY ARE interested in the film

2 , Although she is old , she works hand 

⇒Dispite her old age,  she works hard

3 , we ofter cycled to school two years ago 

⇒We used to cycle to school two years ago 

4 , He set offf early , but he arrived late 

⇒Although  He set offf early , he arrived late 

5 , The distance from ha noi to can tho is about 1 , 887 km

⇒It is bout 1 , 887 km from ha noi to can tho 

Cách này cũng đúng nhưng có cách khác nhanh hơn

S = ( 5 + 5^2 + 5^3 + 5^4 ) + .....

Gộp 4 số liên tiếp lại rồi C/M

Chúc học tốt