Cho tam giác ABC có các đường cao AD, BE, CF. CMR ABC là tam giác đều nếu `\vec{AD}+\vec{BE}+\vec{CF}=\vec{0}`

Mọi ngưòi giúp em bài này với ạ

helllllppppppppppppp...................

Làm và giải thích ạ 1) The Sultan spent over fifty million dollars making the capital city's main hotel the most……… in the country. (luxury) 2) Police working on solving the bank robbery have by chance…………… a plan to murder a leading politician. (cover) 3) We should go and eat at "Franco's" which is………….. a great little restaurant. (suppose) 4) I left the house at 8am and stared at the empty garage in………….. My car was nowhere to be seen. Someone had stolen it! (believe) 5) If you have any problems finding things, just ask Roger. He is very…………… and will tell you where to find what you want. (help) 6) You paid $25 for a simple breakfast?! They have certainly…………… you! You should go back and complain. (charge) 7) The gang robbed three banks in the same city and all at about the same time. Not……….., they were caught by the police during the fourth attempt. (surprise) 8) Sarina is only my half sister because we have………… mothers. (differ) 9) This queue hasn't moved in five minutes. I'm getting a bit………….! (patient) 10) Politicians should spend some time living on the streets like………….. people have to and then they would understand better the problems they have. (home) 11) Carl was calmly taking a photograph as this………….. large bear walked towards the car. It was a terrifying experience...at least for me! (astonish) 12) If you go walking around the factory, ensure you have…………… clothing on. (protect) 13) Are you sure you have cleaned the kitchen? There is still a pretty………….. smell coming from it. (pleasant) 14) Although it isn't definite we will see you tomorrow, it is quite………….. (like) 15) Be sure not to put more than three……………… of vodka into the mix, otherwise it will be too alcoholic. (spoon) 16) Finding a cure for cancer will be a huge ………….breakthrough for mankind. (medicine) 17) Buying and selling antiques can be a very …………..hobby if you know how to find a good bargain. (profit) 18) We were left without any money for the last part of our holiday because we had ………… the cost of the train ticket to Norway. (estimate) 19) Mr. Transom stared ………….. at the group of students talking in the corner and they shut up immediately. (cross) 20) Jennings is so …………enthusiastic about the game that his enthusiasm spreads to his team-mates and the result is usually a strong performance. (wonder)

Giải đúng công thức lớp 7 nha 1) Tìm hai số dương biết, 7 lần số I bằng 3 lần số II và hiệu của chúng là 100. 2) Tỉ số của 2 số nguyên dương là 3/7. Tổng các bình phương của chúng bằng 522. Tìm hai số đó.

Cho `\vec{u}, \vec{v} \ne \vec{0}` và cùng phương, các số a, b, c, d thỏa mãn: `a.\vec{u}+b.\vec{v}=\vec{0}` và `c.\vec{u}+d.\vec{v}=\vec{0}` CMR: `a/b=c/d`

Giúp mình vs 19h20 mình phải mộp r hứa trà 5 sao

Rewrite these sentences, keeping the original meaning 7, I can't cook as well as my mother. My mother can cook hedier 8,He does not play tennis as well as Jack.→ Jack can 9,1 did not spend as much money as you. → You spent_ 10,1 don't think this book is expensive as it is. This book is 11,He is the tallest boy in his class. → No one in 12, This is the most interesting film of all.→ No other films are No cars in the world are more expensive than Japanese ones.→Japanese cars 13,This exercise is easier than that one. - That exercise is not 14,He drives more carefully than Jack does. - Jack He can 15,No one in the group plays better than he. -> 16,No hotel in the city is as comfortable as this. This hotel is the 17,0ther oceans in the world aren't as large as the Pacific one. The Pacific Ocean is nloto the nassage below

Hai dòng điện có cường độ I1 = 2A, I2 = 4A chạy trong hai dây dẫn thẳng dài vô hạn, đồng phẳng, vuông góc với nhau đặt trong không khí. Trong mặt phẳng chứa hai dòng điện, quỹ tích những điểm tại đó véc tơ cảm ứng từ tổng hợp bằng 0 là đường thẳng(trừ điểm gốc tọa độ O):

So trung binh cong cua 2 so la 36.Biet mot trog 2 so do la 50,tim so kia