Vote 5 sao và câu trả lời hay nhất!!!help me!. Bài 1: Dùng hằng đẳng thức để khai triển va thu gọn các biểu thức sau: a) ( a^2b + ab^2 )*( ab^2 - a^2b ) b) ( 3x - 4 )^2 + 2*( 3x - 4 )*( 4 - x ) + ( 4 -x )^2 c) ( 3a - 1)^2 + 2*( 9a^2 - 1) + ( 3a + 1)^2 d) ( a^2 + ab + b^2 )*( a^2 - ab + b^2 ) - ( a^4 + b^4 ) Bài 2: Tính: ( 20 + 18^2 + 16^2 +....+ 4^2 + 2^2 ) - ( 19^2 + 17^2 + 15^2 +....+ 3^2 + 1^2) . Bài 3: Cho hình thang ABCD có đáy AB và CD , biết AB = 4cm , CD = 8cm , BC = 5cm , AD = 3cm . Chứng minh ABCD là một hình thang vuông. Bài 4: Cho tam giác MNK cân tại M có đường phân giác MH . Gọi I là một điểm nằm giữa M và H . Tia KI cắt MN tại A , tia NI cắt MK tại B . a) CMR: ABKN là hình thang cân b) CMR : MI vừa là đường trung trực của AB vừa là đường trung trực của AN Các bạn giúp mình với.

Cho tam giác ABC vuông ở A, có B = 60°, tia phân giác của góc ABC cắt AC ở E, kẻ CD vuông góc với đường thắng AE (D thuộc AE). a) Tính số đo các góc ACB, EBA và EBC b) Chứng minh: EC = EB c) Chứng minh: BD= AC mn ơi mk đang cần gấp. giúp đỡ mk cảm ơn nhìu

16. Mai (live) ________ in Hai Phong for five years before she (move) _________ to Ha Noi three years ago. 17. Phong (tell) __________ me yesterday that he (learn) _________ French for a year. 18. Ms. Hong (work) _______ at our school for twenty years before she (retire) _______ last June. 19. By the time I (get) _________ to Nick’s house, his party (already/ start) _____________. 20. I couldn’t recognize my cousin because he (grow) _________ up a lot.

u SHOULD – SHOULDN”T 1. There are captivities in the boys’ teeth. I think they ______ eat too many candies. A. must B. mustn’t C. should D. shouldn’t 2. You _______ be ashamed of yourselves. A. could B. should C. did D. would 3. We ___________ do something immediately to save the Earth from being destroyed A. could B. should C. did D. would CORRECTION: 1. Hue said me that she would come home the next Monday. A B C D 2. We are looking forward for going on a wonderful summer holiday. A B C D 3. If I have to fly, I would get very nervous, so I usually drive. A B C D 4. Ms. Thuy told that she didn’t mind taking care of disabled children. A B C D 5. The children won’t go to sleep if we left a light on outside their bedroom. A B C D 6. Children are always looked for by their parents A B C D 7. Television now takes such an important role in so many people’s life. A B C D 8. We should turned off the lights in the classroom before we go home. A B C D SPEAKING: 1. “Are you free going to my birthday party tomorrow?” __________ A. Certainly, Here you are. B. No problem. I’m Carol. C. Ok. I’ll come. D. It’s pleasure to meet you. 2. “ Let’s join us in this trip.” __________ A. I’m doing very well. How about you? B. I’ve been to Da Lat? Are you? C. You’ve been very nice to me. Thanks. D. I’m sorry I can’t. Have a nice trip! 3. “ How about fishing at the weekend?”________ A. That sounds great. B. Thanks. C. You can do it. D. No problem. 4. “ Shall we play a game of table tennis now?”__________ A. Not at all. B. You are welcome. C. Sorry. I’m too tired. D. I don’t know you did it.

Tìm số đối của các số-10012;2003;-199

I. Read the following passage and choose the best option. It’s hard to imagine education without (1)__________. Without energy, people’s ability to get a decent education is severely (2)__________. Education is acknowledged as a crucial factor in helping people escape (3)__________ poverty. In communities without energy children are often forced out of school to help (4)__________cooking (5)__________or earn money. When they do go to school it has to be in (6)__________, which restricts their hours especially as many children walk for hours to get there. When they arrive home to do their schoolwork, they have no (7)__________to study and all that greets them is darkness. Or they have to rely on kerosene to provide precious light, which is both expensive and dangerous; if a lamp is knocked over it can cause serious burns. Computers, radio or TV are important tools in the (8)__________ education. A (9)__________ of electricity restricts the (10)__________for children to further their education. And teachers don’t want to work in communities where there are no lights, little equipment, no TVs, computers or life after dark. 1. A. like B. energy C. such as D. similar 2. A. approximately B. expressively C. affected D. progressively 3. A. from B. pioneering C. pioneering D. pioneers 4. A. custom B. waiter C. collect D. pill 5. A. tourists B. materials C. pilot D. guess 6. A. Orbit B. Orbition C. Orbital D. daylight 7. A. light B. designed C. draw D. painted 8. A. equipment B. tool C. modern D. furniture 9. A. invitation B. lack C. space D. aviation 10. A. landscape B. departures C. islands D. opportunity

1) The boys stood on the desks. They wanted to get a better view => 2) We learn English . We want to have beeter communication with other people => 3) We lower the volume .We don't want to bother our neighbours => 4) I will write to you .I want you to know my decision => 5) These grils were talking whispers . They didn't want anyone to hear their conversation => Chỉ cần ghi kết quả mik cảm ơn rất nhiều

Bài 1: Giải các hệ phương trình sau: a, {7x + 5y =19 b, { x + 5y =-5 c, { 2x + 3y =-2 3x + 5y = 31 3x + 2y = 11 3x - 2y =- 3 Bài 2: Tìm hai số tự nhiên, biết rằng tổng của chúng bằng 1006 và nếu lấy số lớn chia số nhỏ thì được thương là 2 và số dư là 124. Bài 3: Tìm các giá trị của m để hệ phương trình sau vô nghiệm: { mx + 2y = -2 3x - y =5 Giúp mình với ạ. Xin cảm ơn.

B= ( căn 3 x^2y^3)^2.(-2/3xy^2)^3 Chỉ giúp mình câu này với mình đang cần gấp lắm lunmnnn á

Tính giới hạn lim từ x-> 2 (/x^2+5 -3 / x-2)