Cho mình hỏi tứ giác có 2 đường chéo vuông góc và 1 góc vuông là tứ giác gì

Cho pt x²-2x+m-1=0(m là tham số)tìm các giá trị của m để pt có hai nghiệm x¹,x² thoả mãn

Tìm số tự nhiên có 2 chữ số, biết rằng nếu viết thêm chữ số 3 vào bên trái số đó thì ta được một số có 3 chữ số và bằng 3/4 số khi viết chữ số 3 vào bên phải của số có 2 chữ số đó.

Các nhà toán học cổ Trung Quốc đã dùng phân số 22/7 để xấp xỉ số π. Hãy đánh giá sai số tuyệt đối của giá trị gần đúng này, biết: 3, 1415 < π < 3, 1416

Làm giùm em bài 2 vs Giải kĩ giùm em nhé

tích sau tận cùng có bn chữ số 0 liền nhau A=1x2x3x....x50

1)Read the passage below carefully and fill in each blank with the correct option A, B, C, or D. WAYS TO IMPROVE YOUR ENGLISH BY YOURSELF a) Virginia Lang, an Australian English teacher, shares her tips on improving your English by yourself.First, change the language settings on your devices such as phones or laptops to (1)____ It forces you to think in English all the time and it will help you to (2)____ more quickly.Second, read with your passions. Read something you are interested (3)____. If you're into sport, read a sports magazine. When you read, read actively and consider the tools that you can use while reading. Highlighters are great for highlighting new words (4)____ you do not know. Have a good online dictionary or a good paper dictionary so that you can check the definition and put it to memory as well.Third, listen to podcasts and watch videos and television in English. You should also write down or say aloud summaries of what you have heard or watched. (Adapted from www.abc.net.au) 1. A. Italian B. French C. Vietnamese D. English 2. A. improving B. improved C. improve D. improvement 3. A.in B. whom C. who D. whose 4. A. can B. will C. have D. are b) The Internet has rapidly developed and become part of (1) ......... daily life. It’s a very fast and convenient way to get information. Peeople use the Internet (2) ............ many purposes: education, communication, entertainment and commerce. The Internet (3) .................. people communicate with friends and relatives by means of email or chatting. (4) .............., the Internet has limitations. It is time consuming and costly. It is also dangerous because of virus and bad programs. On the other hand, people (5) .................. the Internet sometimes have to suffer various risks such as spam or (6) ................ junk mails, and personal information leaking. So, while enjoying surfing, be alert! 1. A. us B. our C. ours D. we 2. A. for B. of C. in D. at 3. A.gives B. helps C. takes D. asks 4. A. So B. Therefore C. However D. But 5. A. whom B. which C. why D. who 6. A. electronic B. electricity C. electric D. electrically c) People love dolphins because they are beautiful to (1) ............. and friendly. Dolphins are also one of the cleverest animals and are jus as clever as dogs. It is possible to teach (2) ............ in the same way we teach monkeys and dogs. Some people even believe that dolphins have a special (3) ............ of talking to each other. (4) ............... many other sea animals and fish, dolphins are in danger. Many dolphins are caught by mistakes in fishing nets, but a much greater problem is that thousands of dolphins are dying (5) ............... the sea is no longer clean enough. 1. A. eat B. feel C. listen D. watch 2. A. their B. theirs C. they D. them 3. A. way B. road C. street D. device 4. A. Like B. As C. For D. So 5. A. and B. but C. so D. because 2) Fill in each numbered blank with a suitable word from the box to complete the passage. interesting to for get channels have and Nowadays Thanks (1)_______________ television people can (2)_______________ the latest information and enjoy (3) _______________ programs in an inexpensive and convenient way. (4)_______________, viewers can watch a variety of local and international programs on different (5) _____________. It brings events (6)_____________ sounds from the world into millions of homes. 3) Fill in each numbered blank with one suitable word from the box to complete the passage. For sellers customers with from was Today, supermarkets are found in almost every large city in the world. But the first supermarket (1) ___________ opened only fifty years ago. It was opened inNew Yorkby a man named Michael Cullen. A supermarket is different (2) ___________ other types of stores in several ways. In supermarkets, goods are placed on open shelves. The (3) ___________ choose what they want and take them to the checkout counter. This means that fewer shop assistants are needed than in other stores. The way products are displayed is another difference between supermarkets and many other types of stores; (4) ___________ example, in supermarkets, there is usually a display of small inexpensive items just in front of the checkout counter: candies, chocolates, magazines, cheap foods and so on. Most customers who go to a supermarket buy goods from a shopping list. They know exactly what they need to buy. They do the shopping according to a plan.

Jerry và George đang chạy bộ dọc theo một con đường tròn. Nếu Jerry chạy thêm 400m nữa thì anh ta đã hoàn thành 2 vòng. Nếu George chạy thêm 500m nữa thì anh ta đã hoàn thành 3 vòng. Tổng quãng đường họ đã trải qua là 100m hơn 4 vòng. Chiều dài của 1 vòng, tính bằng m?

cau 4 cau van "Tre la ban than cua nhan dan Viet Nam" co phai la cau tran thuat don khong? vi sao?

Helppp KHÓ QUÁ HELPPPPPPPPL MEEEEEEEEEE.....