trả lời :

 pp

^HT^

=x³-2xy²+y³+2xy²

ta thay x=1 và y=-2,ta có:

=1³-2*1*(-2)+(-2)³+2*1*(-2)²

=1+4-8+8

=5

HOK TỐT ^.^ 

A = 4x^3 + 15x^2 + 24x + 3 + a 

B = x^2 + 4x + 7 

=> A : B hay ( 4x^3 + 15x^2 + 24x + 3 + a ) : ( x^2 + 4x + 7 ) = 10 + a 

Để A chia hết B 

=> 10 + a = 0 <=> a = -10 

a)Vì đa thức dư 10 + a nên a = -10 thì A\(⋮\)B.

b) Vì đa thức dư là (2a-3)x + 3b + a 

nên \(a=\frac{3}{2};b=-\frac{1}{2}\)thì \(A⋮B\)

+)\(\Delta ABC\)có

F là trung điểm của BC

H là trung điểm của AC

=>FH là đường tb

=>FH=\(\frac{1}{2}\)AB\(\Rightarrow AB=2cm\)

+)Tương tự ta dễ dàng chỉ ra đc EH là đường tb của \(\Delta ADC\)

\(\Rightarrow EH=\frac{1}{2}DC\Rightarrow EH=2cm\)

Vậy EH=AB=2cm (hay x=y=2cm)

ta có:FB=FC,HA=HC gt

suy ra fh l;à đg trung b́nh của tam giác ABC

suy ra HF bằng 1/2 AB ,AB SONG SONG HF

suy ra 1 bằng 1/2 AB

suy ra AB=1:1/2

suy ra AB=2 hay =2

TA LẠI CÓ F LÀ TRUNG ĐIỂM CỦA BC 

HF SONG SONG AB SONG SONG DC

SUY RA È LÀ ĐG TRUNG B̀NH CỦA H̀NH THANG ABCD

SUY RA EF=AB+DC TRÊN HAI

SUY RA EF={2+4}:2

SUY RA EF BẰNG 3

SUY RA EH=3-1

SUY RA EH=2 HAY Y =2

VẬY.....

MẤY CHỖ SUY RA TỰ THAY NHÉ

MÁY TÍNH MK KO BẤM ĐC DẤU NGOẶC VỚI SUY RA

VIẾT CÁI NÀY HƠN 10 PHÚT NÊN  TÍCH CHO MK NHÉ

HỌC TỐT

\(=\frac{\left[\left(1502-1\right)\left(1502+1\right)\right]\left[\left(1499+1\right)\left(1499-1\right)\right]}{6002}\)

\(=\frac{\left(1502^2-1\right)-\left(1499^2-1\right)}{6002}=\frac{2256003-2247000}{6002}=\frac{9003}{6002}=1,5\)

\(D=\frac{1501.1503-1500.1498}{6002}\)

\(\Leftrightarrow D=\frac{\left(1502-1\right)\left(1502+1\right)-\left(1499+1\right)\left(1499-1\right)}{6002}\)

\(\Leftrightarrow D=\frac{1502^2-1-1499^2+1}{6002}\)

\(\Leftrightarrow D=\frac{\left(1502-1499\right)\left(1502+1499\right)}{6002}\)

\(\Leftrightarrow D=\frac{3.3001}{6002}=\frac{9003}{6002}=\frac{3}{2}\)

\(C=\frac{1999.4001+2000}{2000.4001-2001}\)

\(\Leftrightarrow C=\frac{\left(2000-1\right).4001+2000}{2000.4001-2001}\)

\(\Leftrightarrow C=\frac{2000.4001-4001+2000}{2000.4001-2001}\)

\(\Leftrightarrow C=\frac{2000.4001-2001}{2000.4001-2001}=1\)

 \(D=\frac{1501.1503-1500.1498}{6002}\)

\(\Leftrightarrow D=\frac{\left(1502-1\right)\left(1502+1\right)-\left(1499+1\right)\left(1498-1\right)}{6002}\)

\(\Leftrightarrow D=\frac{1502^2-1-1499^2+1}{6002}\)

\(\Leftrightarrow D=\frac{\left(1502-1499\right)\left(1502+1499\right)}{6002}\)

\(\Leftrightarrow D=\frac{3.3001}{6002}=\frac{3.3001}{2.3001}=\frac{3}{2}\)

 So sánh 1 và 3/2, Ta thấy C<D

\(C=\frac{\left(3000-1001\right)\left(3000+1001\right)+2000}{2000\left(4001-1\right)+1}\)

\(=\frac{3000^2-1001^2+2000}{2000\cdot4000+1}=\frac{9000000-1002001+2000}{8000000+1}\)

\(=\frac{7999999}{8000001}=0,99999975\)

còn câu D mk làm ở câu khác rồi nên mk ghi luôn kết quả nha

D =  1,5

=>  C <  D 

1. F ( dòng 2 )

-> There are a few good buildings ....... 

2. F ( dòng 3 )

-> there are a few parks worth visiting

3. T ( dòng 3,4,5)

-> Everything has to be small in Tokyo: houses, rooms, shops. Long-side streets consist of tiny houses only

4. F ( dòng 2 đoạn 2 )

-> Millions of neon lights are switched on and nowhere in the world is more attractive

5. F ( dòng 4 đoạn cuối ) 

-> Tokyo may lack architectural.......

1.B

2.B

3.A

4.B

5.C

HT~

XI. Read the following passage and choose the best answer A, B, C or D.

      Sydney is Australia’s most exciting city. The history of Australia begins here. In 1788 Captain Arthur Philips arrived in Sydney with 11 ships and 1624 passengers from Britain (including 770 prisoners). Today there are about 3.6 million people in Sydney. It is the biggest city in Australia, the busiest port in the South Pacific and one of the most beautiful cities in the world. In Sydney, the buildings are higher, the colors are brighter and the nightlife is more exciting. There are over 20 excellent beaches close to Sydney and its warm climate and cool winter have made it a favorite city for immigrants from overseas. There are two things that make Sydney famous: its beautiful harbor, the Sydney Harbor Bridge, which was built in 1932 and the Sydney Opera House, which was opened in 1973.

1.   Where did Captain Arthur Philips arrive in 1788?

      A. South Pacific                                              B. Sydney Harbor

      C. Britain                                                        D. Sydney

2.   Which of the following should be the title of the reading passage?

      A. Sydney’s Opera House                              B. The history of Sydney

      C. Sydneys beaches and harbors                    D. An introduction of Sydney

3.   Which of the following statements is NOT true about Sydney?

      A. Sydney is not a favorite city for immigrants from overseas.

      B. Sydney is one of the most beautiful cities in the world.

      C. Sydney is the most exciting city in Australia.

      D. Sydney is the biggest port in the South Pacific.

4.   How many beaches are there close to Sydney?

      A. 11 beaches                                                  B. over 20 beaches

      C.  nearly 20 beaches                                      D. 770 beaches

5.   When was the Sydney Harbor Bridge built?

      A. 1788                       B. 1973                       C. 1932                       D. 1625

ai cứu tui!

1. get, got

12 is

11. Nam always gets grade A in Physics, but last semester he gets B

12. They were proud of was so successful.

Neu thay sai thi bao nha.

Ta có : a^2+b^2 +c^2 >= ab+bc+ac ==> a^2+b^2+c^2+2ab+2bc+2ac>=3(ab+bc+ac) => (ab+bc+ac)<= ((a+b+c)^2)/3 Dấu đẳng thức xảy ra khi và chỉ khi a=b=c Áp dụng : được Max B = 3 khi a=b=c=1
HT

a = b = c 1ht

TTLTL*

HHT