các khẳng định sau đây có đúng với mọi số nguyên a:b không? nếu sai hãy chỉ ra một ví dụ a,a=b suy ra(a)=(b) b,(a)=(b)suy ra a=b c,a>b suy ra(a)>(b) d,(a)>(b) suy ra a>b e,(a)>0 g,n lớn hơn hoặc bằng (a) h,(a).b=(a)(b) f,(a)+b=(a)+(b)

Giúp mình giải câu 7 8 ( có lời giải) tks

Một người dùng búa tác dụng một lực 450 N vào một cái đinh làm nó ngập sâu vào gỗ một đoạn 1 cm. Nếu người đó dung lực 430 N thì phải đóng 2 lần đinh mới ngập sâu vào gỗ 1 cm. Đóng đinh bằng cách nào ít tốn công hơn? vì sao?

III. Rewrite the following sentences as directed. 1) I get to work in half an hour. => It takes 2) Keeping the environment clean is very important. => It’s 3) The building has five floors. => It’s 4) Nam likes staying at home than going to the zoo. => Nam prefers 5) Would you like to go out for dinner tonight? => Let’s I. IV. Choose the word (A, B, C or D) that the best fits the blank in the following passage. 1/Hoa is writing a letter to her mom. She says that she is glad (1) ________ her parents were well. She is doing well at school now. At first, everything was strange and (2) ________ . But she is having a lot of fun at the moment. She hopes her parents (3) ________ Ha Noi after the harvest. She will show her parents (4) ________ the city. And she will tell her parents (5) ________ about her because she knows (6) ________to take care of herself. 1. a. hear b. to hear c. to hearing d. hearing 2. a. difficult b. different c. hard d. a & c 3. a. visit b. will visit c. visits d. visiting 4. a. around b. of c. at d. on 5. a. not worry b. not to worry c. worried d. to not worry 6. a. how b. what c. why d. who 2/ On June 2nd (1) ________ year, I traveled to Dalat (2) ________ my parents. We (3) ________ in ThanhBinh Hotel for a week. We visited many places such as Xuan Huonglake, Love valley and a lot of beautiful waterfalls. After that we went to (4) ________grandparents’ house in Ho Chi Minh City and stayed there (5) ________ five days. We visited Botanical Garden, and Ben Thanh market. Our holiday (6) ________ very wonderful. We returned to Ha Noi on June 17th. 1. a. next b. last c. this d. that 2. a. to b. along c. with d. and 3. a. stay b. will stay c. staying d. stayed 4. a. us b. our c. him d. his 5. a. in b. with c. at d. for 6. a. is b. was c. are d. were

3 Câu 40 điểm nhé, hứa vote 5✮!

xin các anh chị em trả lời cả hai câu giúp mình với

các b giải chi tiết hộ mình câu 48 đến 50 với ạ

Làm giúp mình BÀi 4 câu 1 2 3 Giúp mình :(((

1/ giải bất phương trình sau : (x-2)(-5x+4)<0

Xét xem tổng (hiệu) nào sau đây chia hết cho 8: a) 400-144 ; b) 80+25+48 ; c) 32+47+33