2x^2+4x+5=2(x^2+2x+1)+3=   2(x+1)^2+3

ta thay 2(x+1)^2  >=0 voi moi x

suy ra 2(x+1)^2+3  >=3 voi moi x

suy ra MIN =3 khi va chi khi x+1=0  <=> x=-1

1.They play football eacs other last week

2.Yesterday, I got up at 6 and had breakfast at 6:30

n=4 vì 5x4+1 chia hết cho 7(đang còn các số khác nữa , tích mình mình giải tiếp)

1:She will get join the fun

2: The manager of the office told her her about her work there

3:The manager say that her work was to help him to write and send letters, make appointments, receive and answer telephone calls and write the reports

4:She listened to him and worked very hard

5:The manager felt very pleased about Mrs.Susan

CHÚC BẠN HỌC TỐT NHA : V

My name is Huong , I am 12 years old.I study at Xuy Xa secondary school.I live in Xuy Xa commic , My Duc distric , Ha Noi city. There are 5 people in my family : my parents ,my older brother, my little sister and I.In my free time , I like reading book , because it helps me learn many things about the world , space, animals , plants , and so on...In my future , I want to go to My Duc A high shool and become a translater.

CHÚC BẠN HOK TỐT NHA !!!!! ^-^

Does she have a beautiful dress ?

ọe tởm vãi cả luỳn......

Ha Noi is very crowded and it has to face a lot of problems. There are too many people using the roads. All types of vehicles are on the roads.It is very dangerous if you are not familiar with transportation here. There are some roads which are narrow and swampy when there is heavy ram.Moreover , some young people drive on the road dangerously.They do not respect the traffic rules stricly and they even play on the street with their motors.

Dễ mà bạn.Chính vì nó dễ cho nên tự làm nha

1.B

2.C

3.D

4.C

5.C

6.C

7.B

8.C

9.B

10.B

11.B

12.A

13.A

14.C

15.C

16.B

17.D

18.B

19.c

20.B