Đáp án:
Giải thích các bước giải:
a)(x+y)²+(x-y)²
=x²+2xy+y²+x²-2xy+y²
=2x²+2y²
b)2(x-y)(x+y)+(x+y)²+(x-y)²
=(x+y+x-y)²
=(2x)²
=4x²
c)(x-y+z)²+(z-y)²+2(x-y+z)(y-z)
=(x-y+z)²+(y-z)²+2(x-y+z)(y-z)
=(x-y+z+y-z)²
=x²
CHÚC BẠN HỌC TỐT CHO MK CÂU TRẢ LỜI HAY NHẤT NHÉ
a) `(x+y)^2 +(x-y)^2`
`=(x^2 +2xy+y^2)+(x^2 -2xy+y^2)`
`=x^2 +2xy+y^2 +x^2 -2xy+y^2`
`=2x^2 +2y^2`
b) `2(x-y)(x+y)+(x+y)^2 +(x-y)^2`
`=(2x-2y)(x+y)+(x^2 +2xy+y^2)+[x^2 +(-y)+(-y)^2]`
`=(x+y+x-y)^2`
`=2x^2`
`=4x^2`
c) `(x-y+z)^2 +(z-y)^2 +2(x-y+z)(y-z)`
`=(x-y+z)^2 +2(x-y+z)(y-z)+(y-z)^2`
`=(x-y+z+y-z)^2`
`=x^2`
giúp e với gấp e sẽ cho 5 sao ạ
Vẽ cự giải hoảng sợ trong truyện lớp học mật ngữ đuy NL: Đọc lại thấy hay
Viết lời bài hát : Cotton Candy Skies ( 1 đoạn hoặc viết hết cx đc )
giải bpt sau: a) ($x^{2}$ -1)($x^{2}$+5x+6)=0 b) ($x^{2}$ - 6x)$^{2}$ -2(x-3)$^{2}$ = 81 c) x(x+1)(x=2)(x=3)=120 d) $x^{3}$ + 5$x^{2}$ - 10x - 8 = 0
Bài 2. Một người đi từ A đến B, trong nửa đoạn đường đầu đi bằng xe máy với vận tốc 10 m/s, trong nửa đoạn đường sau đi bằng ô tô với vận tốc 60 km/h. Tính thời gian chuyển động của người đó biết khoảng cách từ A đến B là 45 km.
mn giup e nhanh v ạ e đang cần gấp.hứa vote 5 sao
Bài 1. Hãy tính thời gian ánh sáng truyền từ ngôi sao gần nhất đến Trái đất. Biết khoảng cách từ ngôi sao đó đến Trái đất là 4,3 năm ánh sáng và vận tốc ánh sáng xấp xỉ 3 00 000 km/s.
Câu IX: Hoàn chỉnh câu thứ hai sao cho không thay đổi nghĩa so với câu đã cho: (1,2 điểm) 1. People should use energy-saving bulbs to save electricity. → Energy-saving bulbs ……………………………………………………………..…….. 2. “When the sun rises, I feel like singing,” Kitty said. →Kitty said that ………………………………………………………………………………….. 3. Practice English everyday or you can not improve your English. →Unless …………………………………………………………………………….………. 4. She has taught her children to play piano for 4 years. →She started………………………………………………………………….…….. 5. New York City is the busier than any other city in the world. →New York City ………………………………………………………….………. 6. We had to put off our trip to Himalaya because of the bad weather, → Because ………………………………………………………………
4. The Lao are one of ……………… many Thai- speaking peoples. A. the B. a C. an D. A and C 5. A tent can be ……………..pulled down and transported than a ger. A. more easily B. more easy C. easier D. as easily 6. Although there are cultural …………… between ethnic groups, they still keep the identity of their own culture. A. relations B. exchanges C. changes D. differences 7. My son is addicted …………………Pokemon Game. A. to play B. with play C. on playing D. to playing 8. ………………..……….has a larger population, the Tay or the Ede? A. What ethnic group you think B. Which ethnic group do you think C. Which ethnic group you think D. What ethnic group do you think 9. Human beings are much ……………….than dogs at detecting smells. A. badder B. more bad C. worse D. worst 10. Building a house is much ………………than putting up a tent. A. difficulter B. more difficult C. difficult D. difficultest 11. The Yao people use ideograms of Chinese origin to write their …………………. A. writing system B. culture C. poem D. language * Circle one word that does not belong in each list 12. A. costume b. skirt C. blouse D. shawl
Practical stress management can help students deal with their worries and become more productive, competent and efficient. First of all, students must be able to design and stick to a timetable. Choose a relaxing break between work and study, even if it’s just taking out time to breathe. In addition, a healthy lifestyle is essential for students. Let’s drink more water as well as take out time to get some air and exercise. Furthermore, organization is very important in academic life for dealing with stress. By keeping academic notes organized, turning in assignments on time, and keeping track of all deadlines, stress can be reduced to a great extent. Stress can also get worse if a person feels lonely. Therefore, by letting out all your thoughts to someone you trust, you immediately feel a lot better. However, if you feel extremely stressed out, take a break and do something you love. Whether it is painting or listening to music, doing something you enjoy can cheer up your mood and distract you from a stressor. It’s about time that we students accept that we can achieve just as much in life without all the stress. 1. Practical stress management can help students . A. deal with stress B. have more time C. face up to the worst situation D. think critically 2. What should students pay attention to when designing a timetable? A. They have to arrange time to breathe. B. They need to set time for relaxation. C. They don’t need to take notice of certain tasks. D. They should stop working and studying. 3. What does the word reduced mean? A. increased B. went up C. decreased D. lessen 4. Which of the following sentences is true? A. You should stay alone when being under pressure. B. When you feel lonely, you should grab someone to talk. C. The more lonely you are, the more stress you can have. D. It is believed that stress can control itself
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