Hoàng Minh NguyệtYến Nguyễn~~ NK Đại Tỷ ~~Thảo PhươngThảo Phương Vũ Thị Thúy Hằng Ngọc ThùyAn Le NguyenLê Thị Hải KhánhNguyễn Thị Hương

Vũ Minh TuấnThảo PhươngNguyễn Phương Thảotrần thị diệu linhĐỗ Hương GiangHoàng Minh NguyệtMai NguyễnNguyễn Trần Thành ĐạtTrần Thọ ĐạtTrần Thị Hà MyLinh Phương

\(x\times\dfrac{20}{11}=\dfrac{1}{1}-\dfrac{1}{3}+\dfrac{1}{3}-\dfrac{1}{5}+\dfrac{1}{5}-\dfrac{1}{7}+\dfrac{1}{7}-\dfrac{1}{9}+\dfrac{1}{9}-\dfrac{1}{11}\\ x\times\dfrac{20}{11}=\dfrac{10}{11}\\ \Rightarrow x=\dfrac{1}{2}\)

Ta có :

=> X x 20/11 = ( 1 - 1/3 ) + ( 1/3 - 1/5 ) + ( 1/5 - 1/7 ) + ( 1/7 - 1/9 ) + ( 1/9 + 1/ 11 )

=> X x 2/11 = 1 - 1/11 = X x 1/11 = 11/11 - 1/11

=> X x 20/11 = 10/11

=> X = 10/11 : 20/11

=> X = 1/2

\(Xx\dfrac{20}{11}=\dfrac{2}{1}-\dfrac{2}{3}+\dfrac{2}{3}-\dfrac{2}{5}+\dfrac{2}{5}-\dfrac{2}{7}+\dfrac{2}{7}-\dfrac{2}{9}+\dfrac{2}{9}-\dfrac{2}{11}\)

\(Xx\dfrac{20}{11}=\dfrac{2}{1}-\dfrac{2}{11}\)

\(Xx\dfrac{20}{11}=\dfrac{20}{11}\)

\(X=\dfrac{20}{11}:\dfrac{20}{11}\)

\(X=1\)

vậy X = 1

Most of the air pollution results from the burning of fossil fuels, motor vehicles, factories, aircraft and rockets. This can cause acid rain which damages water, soil, and vegetation. Air pollution also contributes to the greenhouse effect which can lead to a series of environmental problems such as global warming, polar ice melting, rise of sea levels and loss of land.

Water pollution is a result of dumping pollutants such as detergents, pesticides, oil, and other chemicals in rivers, which makes the water unclean or contaminated. Rubbish blockages in rivers can also cause pollution.

Soil pollution is a consequence of human activities that alter ecological factors that cross the ecological boundaries of the communities living in the soil. The land environment is home to human beings and most of the shallow creatures, the foundations for civil, industrial and cultural constructions. Land is a precious resource, people use land resources for agricultural production to ensure food supply for people. But with the pace of population growth and the pace of industrial development and urbanization, the area of ​​arable land is shrinking and land quality deteriorates, the average land area head drops. Parularly in Vietnam, the actual depletion of land resources is very worrying and serious.  What do we need to do to protect the environment? That is the question that every one of us needs to answer. In my opinion, protecting the environment is the responsibility of the whole community. Everyone must have a sense of protection. The green, clean, beautiful environment will make our lives better. From the house to the alley, from the alley to the school etc. The place is also clean and airy, many trees, air will be fresh, health will be guaranteed. That everyone wants. At present, I see my class, our school where the concentration of people, not very clean, garbage also lunged, trees are still less. On the street, there are public trash but few people put garbage in the bin, you do not throw it, making the street scene is not beautiful. To protect the environment, I feel we must always have a sense of environmental protection in parular: Do not throw garbage indiscriminately, do not discharge dirty water into ponds, do house cleaning, alleys, schools, not breaking flowers ... and propaganda for people always have common sense and responsibility for environmental protection.

giúp mk water or air thôi nhá bn, 

1. She asked me if I could help her with her bags the following day.

2. If Nam were a teacher, he would help you.

3. Nam ate too much so he was full.

4. They asked Nam if he liked watching movies.

P/S : câu 4 "you" chứ cậu

1. "Can you help me with my bags tomorrow " she said

=> She asked me if I could help her with her bags the following day

2. If/Nam/be/teacher/He/help/you

=> If Nam were a teacher , he would help you

3. Nam was full because he ate too much ( so)

=> Nam ate too much so he was full

4. " Do they like watching movies, Nam" they said

=> They asked Nam if they liked watching movies

Helpp mee

Bạn ơi hình như ra số âm rồi

VD:

- Khi không khí là chất cách điện: Bình thường khi ta đứng gần ổ điện, ta không bị điện giật. Điều đó chứng tỏ không khí ở điều kiện bình thường là chất cách điện

- Khi không khí là chất dẫn điện: Khỉ các đám mây giông phóng điện xuống đất (hiện tượng sét đánh) thì không khí khi đó là chất dẫn điện

Hiện tượng 1: khi ở độ ẩm cao không khí có thể dẫn điện( ko chắc lắm)

Hiện tượng 2: khi dòng điện quá cao như ở những nhà máy phát điện dòng điện lên tới 5000 V nêu trong trường hợp này không khí dẫn diện