Mik tham gia lun nha!LinhKa m trả lại XH hoc24h bình yên cho tụi t!!

(-3.2x+15)+(3.-4x-9)=3x+2

-3.2x+15+3.-4x-9=3x+2

2x+-4x-3x=-3.15+3.-9

2x+-4x-3x=-45+-27

x..(2+-4-3)=-72

x.-5=-72

x=-72:-5

x=-72/-5

1,=>2x-5=15 hoặc 2x-5=-15

...(xét 2 trường hợp rồi tự làm nhé)

2,2xy+2y+4y+4=0

x.(2y+2)+4(y+1)=0=>x(2y+2)=0 hoặc 4(y+1)=0

...(tự làm )

3,x+3=(x-2)+5

do x-2 chia hết cho x-2 mà x+3 chia hết cho x-2

=>5 chia hết cho x-2 =>x-2 thuộc {1;-1;5;-5}=>x thuộc {3;1;7;-3}

4, (y-z)+(z+x)=-10+11

(y+x)+(z-z)=1

y+x=1

kết hợp với x-y=-9 ta đưa ra bài toán tổng hiệu và tìm x và y .

thay x;y vào các điều kiện của bài toán ta tìm được x;y;z

5,xy=x+y

xy-x-y=0

x(y-1)-y=0

x(y-1)-y+1=1( cộng cả 2 vế vs 1)

x(y-1)-(y-1)=1

(y-1)(x-1)=1

=>có 2 trường hợp :

TH1:y-1=1 ; x-1=1

TH2:y-1=-1 ; x-1=-1

bạn tự tìm x;y nhé 

TICK MÌNH NHÉ . XIN LỖI VÌ KO GIẢI CỤ THỂ CHO BẠN ĐƯỢC VÌ MÌNH RẤT BẬN

Read the following passage and choose the best answer to each question.

Predictions about the Cities of the Future

Cities are built to survive and prosper. Over the years, we have learned to transform our surroundings according to our needs. We have cut through mountains to make more land and created artificial islands to make skyscrapers. City planning, as an organized profession, has existed for less than a century. However, a considerable amount of evidence (both archaeological and historical) proves the existence of fully planned cities in ancient times. Over the years, humans have made some mistakes in terms of using an excessive amount of resources for cities. This gives rise to the question of how sustainable the cities of the future would be. We might be looking at smart cities in which street lights would only switch on when you are close by and traffic light would be eliminated by smart driving. The cities of the future would try to save our resources rather than deplete them. An example of an advanced city is Kansas. Plans are in place to make Kansas a smart futuristic city in the future. Planners are considering introducing sensors to monitor the water mains. Warning would be issued to city officials when the infrastructure requires repair or replacement. In this way, the city would never be at risk of having broken pipes. While the idea sounds fantastic, a large amount of rational critique has called this plan an oversold dream. Amy Glasmier is an urban planning professor at MIT. She is a smart city skeptic who believes that all the research and talk is great but gravely oversold.

Question: City planning is thought_______.

A. to have become a profession for about a hundred years

B. to have existed professionally since ancient times

C. to have come into existence to transform nature

D. to make more land and created artificial islands to make skyscrapers

này Uzumaki

đáp án là 15 người

Số bé nhất có hai chữ số khác nhau là 10

các bn tick cho mk nha.cảm ơn nhiều.

Giá trị của biểu thức 300 - 200 - 100 là:

A. 300

B. 200

C. 0

D. 100