a²(b-c) + b²(c-a) + c²(a-b)
=a²b - a²c + b²c - b²a + c²a - c²b
=a²b - a²c + b²c - b²a + c²a - c²b - abc + abc
=a²b -a²c -b²a + abc - abc + c²a + b²c - c²b
=a(ab - ac - b² + bc) - c(ab - ac - b² + bc)
=ab - ac - b² + bc(a-c)
=a(b - c) - b(b - c)(a-c)
(a-b)(b-c)(a-c)
$VT=a^2(b-c)+b^2(c-a)+c^2(a-b)$
$=a^2b-a^2c+b^2c-ab^2+ac^2-bc^2$
$=(a^2b-a^2b)-(abc-b^2c)-(a^2c-abc)+(ac^2-bc^2)$
$=ab(a-b)-bc(a-b)-ac(a-b)+c^2(a-b)$
$=(a-b)(ab-bc-ac+c^2)$
$=(a-b)[(ab-ac)-(bc-c^2)]$
$=(a-b)(b-c)(a-c)=VP$ $(đpcm)$.
VIẾT MỘT BÀI TẢ CẢNH BÌNH MINH VÀ CẢNH HOÀNG HÔN
Là hs, e cần lm j để chấp hành tốt pháp luật
Cho ba số thực dương a,b,c tm abc=1 CMR (a^2+b^2+c^2)^2 >=9(a+b+c)
a) 8+x^3 b) x^3-27 c) 1- 4x^2 d) 9x^2 - 4 e) x^2 - 4x+4 f) 8x^3 +64 g) 1-2y+y^2 h) 16-24y+9y^2 i) 4x^2-4x+1 j) x^3+3x^2+3x+1 k) 9x^2+6x+1 l) x^2-8x+16 m) 100x^2-(x^2+25)^2 n) (x-3)^2 -16 o) 27 - 8x^3 phân tích thành nhân tử giúp mình với nhé
Có ai học ở đức trí ko Vẽ cho mình một bộ võ phục Taekwondo nha(hoặc võ phục môn nào cx dc)
Exercise 2: Read and arrange the headlines into each paragraph. - Set up a compost bin - Explore the idea of purchasing energy-efficient appliances - Make your own non-toxic cleaning products - Grow an organic garden WAYS TO MAKE GREENER WORLD 1. Doing this will reduce the use of plastics because you are reusing plastic containers to hold the cleaning products. The ingredients are also biodegradable which means it is gentler on the environment. 2. Being able to rely on yourself for fresh produce is very rewarding. Share your harvest with neighbors and preserve the excess for years to come. If you don’t have the space or time to grow a garden, shop locally and support local farmers. 3. Add a few less things to the landfill by composting your kitchen scraps. All plant-derived foods, coffee grounds and tea leaves can be composted. Have a small container in your home to place items in. When the storage container gets full, transfer the waste to an outdoor bin. Use the results to enrich fertile soil in the garden. 4. They may cost more upfront but in the end you will save money because they use less energy. Replace regular lights bulbs with their energy efficient counterparts. You pay a little more, but the life of the bulb is significantly longer. Exercise 6: Read the text again and answer the questions. 1. What will you do to reduce the use of plastics? . 2. What should you do with the excess of harvest? . 3. "What should you do if you do not have space for growing a garden? . 4. How can you reduce the amount of rubbish? . 5. What can be composted? . 6. What can we do with the composted products? . 7. How energy-efficient appliances help to save money? . 8. Which are cheaper, regular light bulbs or energy efficient appliances? . Exercise 7: Write sentences basing on available information, the first one has been done for you as an example. (Answer may vary). Transportation Material Energy - School bus - Double-side printing - Windows - Bike - Recycling paper - Using recycled paper 0. Children should go to school by school bus. 1. . 2. . 3. . 4. . 5. .
giải phương trình ( bn nào giải nhanh mình sẽ vote 5*)
cho tam giác abc có diện tích bằng 540 cm2 .Gọi m,n lần lượt là điểm chính của ab và ac .Tính diện tích hình mncb
Vẽ anime bùn i các bác (＠´ー`)ﾉﾞ Digi nha ( tô màu nữa ) ~~
Viết đoạn văn ngắn với chủ đề: Tôi là một đóa hoa.
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