B=|x-2019|+|2018-x|

Mà|a|+|b|>= |a+b| nên ta có:

B>=|x-2019+2018-x|=1

Vậy gtnn của B =1

Dấu = xảy ra khi và chỉ khi ab>=0 tức là (x-2019)(2018-x)>=0 <=>2018=<x=<2019

Tích cho mình vs nha😉

a)-d//b mà b cắt a nên d cắt a

-c//a mà a cắt b nên c cắt b

1.Because of being suffered from a bad cold,Jim was absent from class yesterday.

2.They decided to move the house so as to travel a short distance to work.

3.Although the weather is cold,she wasn't wearing a cold.

4.Because of the heavy rain,i couldn't go to school.

5.He opened the window in order that he wanted to let fresh air in.

6.I've just a CD player,so that i want to give it to my daughter for her birthday.

7.As there was an accident,i was late.

8.Due to her bad grades,she failed the University entrance exam.

9.Because of the polluted water,The fish are dead.

1.b

2.a

3.a

4.a

5.c

6.b

7.d

8.d

9.a

10.d.

With the developments of our country,having a life skill play a vital part to teenagers in Vietnam.In my opinion,communication is one of the most important skills that they really need.First of all,in a modern world,communication is more neccessary,having this skill,youngsters can easily get a good job in the future.As i see,almost every one who is good at communicating achieve a great success in their lives.Secondly,this skill will make you feel more confident in front of crowd,so you can show your ability without any difficult.Everyone will also believe in you.Moreover,communication skill even help you to make friends.It's can't be denied that speech is the fastest way to connect people with each other.Therefore,the better you are at communicating,the more friends you will have.Inconclusion,in my point of view,communicating is a really vital life skill.

goes(có usually=>chỉ 1 hành động diễn ra lặp đi lặp lại nhiều lần=>Hiện tại đơn)

rode(có yesterday=> quá khứ đơn)

1.will rain

2.play( let sone Vbare)

3.studying(spend Ving)

4.on(tobe on TV:phát sóng trên TV)

5.on( on+thứ/ngày)

6.from( far +from)

7.between( vì có and)

8.up(pick up:đón)

9.in(reach in)

10.She has a beautiful oval pink face( a/an+phẩm chất+hình dáng+màu sắc +N)

11.The fridge was not light enough to move upstairs( heavy=not light)

😊

Designers are making different styles of Jeans to match the up-to-date fashions.

a)( a+b)² -2ab = a²+b² +2ab-2ab= a²+b²=> điều phải chứng minh

b)(a²+b²)²-2a²b²= a⁴+b⁴+2a²b²-2a²b²=a⁴+b⁴

c)a⁶+b⁶= (a²)³+(b²)³= (a²+b²)(a⁴-a²b²+b⁴)=(a²+b²)(a⁴+2a²b²+b⁴-3a²b²)= (a²+b²)[(a²+b²)²-3a²b²]

d) a⁶-b⁶=(a²-b²)(a⁴+a²b²+b⁴)= (a²-b²)(a⁴+2a²b²+b⁴-a²b²)=(a²-b²)[(a²+b²)²-a²b²]

a) = (x² - 2xy +y²) + (x² +x +2)

=(x-y)² + (x+1/2)² +7/4 >0 với mọi x,y

=> không tồn tại các số x,y thỏa mãn hằng đẳng thức đã cho.

b) = (x²-2x+1)+(9y²+12y+4)+(4z²-4z+1) + 14=(x-1)²+(3y+2)²+(2z+1)²+14>0 với mọi x,y ,z

=> không tồn tại giá trị x,y,z thỏa mãn đẳng thức đã cho