Người ta dùng một máy có công suất P = 8 WK và hiệu suất H = 80 % để nâng hàng từ mặt đất lên độ cao 5m . Máy đã làm việc trong 12h. Hỏi máy đã nâng được bao nhiêu tấn hàng ?

Cho tam giác ABC vuông tại A có AB < AC. Phăn giác góc BAC cắt đg trung trực cạnh BC ở điểm D. Kẻ BH vuông góc AB và DK vuông góc AC a. Tứ giác ABDK là hình gì? CM b. CM BH= CK c. Giả sử AC =8cm và BC =10cm. Gọi M là tdiem của BC. Tính S tứ giác BHDM

lim( $\frac{1}{n^{2}}$+ $\frac{2}{n^{2}}$ +...+ $\frac{n-1}{n^2}$ )

Exercise 1: Use “not as / so … as” to rewrite these sentences : 1.Lipton tea costs 10$. Oolong tea costs 9 $. 2.Vinh is 1.65 meters tall. Hai is 1.7 meters tall. 3.Mary isn’t big. She was very big last year. 4.You are happier than she looks. 5.My bicycle is more expensive than yours. 5.Tom doesn’t try hard. His brother tried hard. 6.The boy doesn’t run fast. He used to run very fast. 7.Mai is the best violinist in her family. 8.The summer isn’t hot. Last summer it was hot. 9.She is active now. She didn’t use to be active. 10.Jimmy is clever. We think he is clever.

Trả lời hộ mình 3 câu này với B) 2x - 1 = 0 và 3x - ( 8 - x ) =0 C) x +1 =0 và ( x+1) (x+2) = 0 2x mũ 3 - 1 phần 2x = 5x - 1 phần 2x và x mũ 2 - 5 phần 2x = 0

Giúp mik mik với mik cần gấp lắm ạ

Mọi người giúp mình câu này với ạ >< Mình cảm ơn rất nhiều ❤❤❤

a. 15:( 12-15) +2 b. ( 726-38+124 ) - ( 124+ 726 ).

làm cho mk câu 13, 17, 18 nha nhanh giúp vs trc 20h25

Exercise 6: Rewrite these sentences using ‘used to’ 1. There did not use to be many cars on the road before. Now there are…………………………………………………………… 2. My brother was a professor at Ha Noi University some years ago, but now he has a job as an enginneer at a big company. My brother used………………………………………………………… 3. Linh walked to school some years ago but now she cycles there. Linh used………………………………………………………………… 4. My father swam in the pool near his house when he was a boy. My father used…………………………………………………………… 5. There are many green trees in front of my house but now it is a big car park. There used……………………………………………………………… 6. I usually stayed up late to watch football matches last year, but now I don’t. I used…………………………………………………………………… 7. Linda doesn’t live with her parent any more. Linda…………………………………………………………………… 8. My hair is now much longer than that in the past. In the past my hair……………………………………………………….. 9. He is not a poor man any more, but he becomes a rich businessman. He used…………………………………………………………………… 10. Did you often go to the beach when you lived in Nha Trang? Did you use………………………………………………………………..? 11. Mr and Mrs Smith are flying to Ha Noi now. TRAVELLING ……………………………………………………………………………… 12. Van had a motorbike once, but he doesn’t have any more. USED ……………………………………………………………………………… 13. My father usually goes to work by car. DRIVES ……………………………………………………………………………… 14. This part of th city didn’t have traffic jams very often. USE ……………………………………………………………………………… 15. I used to walk to school when I was young. FOOT ……………………………………………………………………………