a²x²+abcx-a²cx-abx²=a²x(x-c)-abx(x-c)=(x-c)(a²x-abx)=ax(x-c)(a-b)
$a²x²+abcx-a²cx-abx²$
$⇔ a²x(x-c)-abx(x-c)$
$⇔ (x-c)(a²x-abx)$
$⇔ ax(x-c)(a-b)$
1. You/ not/ play/ more/ computer games/ free time. ............................................................................... 2. Doctor/ asking/ Mai/ qustions/ about/ health problems. ....................................................................... 3. Vitamins/ play/ important/ role/ our diet. ............................................................................................. 4. We/ keep/ our bodies/ warm/ avoid/ flu/ a cold. .................................................................................. 5. Getting/ enough/ rest/ help/ you/ concentrate/ school. ......................................................................................................................................
18. A new hospital/ been/ build/ Covid-19 patients / local volunteers. * 5 điểm A. A new hospital by local volunteers have been built for Covid-19 patients. B. A new hospital have been built for Covid-19 patients by local volunteers. C. A new hospital has built for Covid-19 patients by local volunteers. D. A new hospital has been built for Covid-19 patients by local volunteers. 19. Their/ complaints/ should/ send/ the head office/. * 5 điểm A. Their complaints should send to the head office. B. Their complaints should be sent to the head office by people. C. Their complaints should be sent to the head office. D. Their complaints to the head office should be sent. 20. Getting together/ crowded places/ ban/ everywhere/ Vietnam/ now/ * 5 điểm A. Getting together are being banned in crowded places everywhere in Vietnam now. B. Getting together in crowded places is being banned everywhere in Vietnam now. C. Getting together in crowded places everywhere in Vietnam is banning now. D. Getting together in crowded places are being banned everywhere in Vietnam now.
1 bài ngắn helpppppp Lm đúng vote 5*
Trình bày suy nghĩ của anh chị về khẩu hiệu covid 19 : " Yêu tổ quốc, yêu đồng bào. Ai ở chỗ nào ở yên chỗ đó " Ai giúp em với ạ
Tính diện tích hình thang AMCD. Biết hình chữ nhật ABCD có: AB = 27cm, BC = 14cm, AM = 2/3AB.
Choose the best answer to complete each of following sentences
X là hỗn hợp gồm hai hiđrocacbon A, B mạch hở, là đồng đăng kế tiếp nhau trong cùng dãy đồng đẳng (trong đó MA<MB). Đốt cháy hết m (gam) X cần 5,04 lít khí oxi (đktc), toàn bộ sản phẩm thu được cho hấp thụ hết vào bình đựng 115ml dung dịch Ca(OH)2 1M thu được 10,0 gam kết tủa, lọc bỏ kết tủa rồi đem đun nước lọc lại xuất hiện kết tủa nữa. Hãy xác định công thức phân tử của A, B và tính % khối lượng của A trong hỗn hợp X ban đầu.
1. Many people _______for posting false information on the Internet. * 5 điểm A. fined B. have fined C. are fined D. was fined 2. I still can’t believe it! My bicycle _______ last night. * 5 điểm A. was stolen B. was stealing C. stolen D. stole 3. Let’s go ahead and do it now. Nothing _______ by waiting. * 5 điểm A. will be accomplished B. accomplished C. has accomplished D. accomplishes 4. “When _______?” - In 1928. * 5 điểm A. penicillin was discovered B. did penicillin discovered C. was penicillin discovered D. did penicillin discover 5. We can’t go along here because the road is _______. * 5 điểm A. been repaired B. being repaired C. repaired D. repairing 6. More than 50 films _______ in HCM city since June. * 5 điểm A. were shown B. had been shown C. have been shown D. have shown 7. The instructions to prevent the disease from spreading _______ precisely. * 5 điểm A. must follow B. must followed C. must to be followed D must be followed 8. When I was a high school student, I _______ a scholarship. * 5 điểm A. used to award B. use to be awarded C. use to award D. used to be awarded 9. Mary _______ that the plan will be changed. * 5 điểm A. has told B. has just been told C. has been just told D. had been just told 10. Many species of rare animals _______ with extinction. * 5 điểm A. is endangered B. are in danger C. threaten D. are threatened 11. The donations ________to the pandemic areas to help the people there to overcome difficulties. * 5 điểm A.are going to send B. are going to be sent C. will send D. are sending 12. The boy donated his saving money to help the poor. * 5 điểm A. The boy’s saving money donates to help the poor. B. The boy’s saving money was donated to help the poor. C. The boy’s saving money is donated to help the poor. D. The boy’s saving money donated to help the poor. 13. The girl cleans the room every day. * 5 điểm A. The room every day is cleaned. B. The room is every day cleaned. C. The room is cleaned by the girl every day. D. The room is cleaned every day by the girl. 14. Nobody violates the regulations of preventing the disease. * 5 điểm A. The regulations of preventing the disease is not violated. B. The regulations of preventing the disease are not violated. C. The regulations of preventing the disease are not violated by somebody. D. The regulations of preventing the disease are not violated by nobody.
Các ac giúp e bài này với ah. E cảm ơn nhiều ah
Trong không khí , hơi nước chiếm gần 1% nhưng lại có vai trò quan trọng vì A. là nguồn gốc sinh ra các hiện tượng mây, mưa... B. ngăn cản tia bức xạ mặt trời. C. Cung cấp nước cho sinh vật. D. Có ảnh hưởng đến đời sống của sinh vật.
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