`x+x+1+x+2+x+3+x+4+...+x+29+x+30=1240`
`(x+x+x+x+...+x+x)+(1+2+3+4+...+29+30)=1240`
`31.x+[(1+29)+(2+28)+(3+27)+(4+26)+...(14+16)+15+30]=1240`
`31.x+[(30xx15)+15]=1240`
`31.x+465=1240`
`31.x=1240-465`
`31.x=775`
`x=775:31`
`x=25`
$\text{Vậy x = 25.}$
Đáp án: x = 25
Giải thích các bước giải:
`x + x + 1 + x + 2 + x + 3 + x + 4 + ....... + x + 29 + x + 30 = 1240`
`(x + x + x + .... + x ) + ( 1 + 2 + 3 + ..... + 29 + 30 ) = 1240`
`x31 + [( 1 + 29) + ( 2 + 28 ) + (3 + 27 ) + .... + 15 + 30 ] = 1240`
`x31 + [15 + (30.15)] = 1240`
`x31 + 465 = 1240`
`x31 = 1240 - 465`
`x31 = 775`
`⇒ x = 25`
Bad students never ( work) hard
Giúp mình với mình cần gấp cảm ơn
Vẽ đậu mầm zui zẻ NL : Cuối cùng cx được ong vàng!!
1. Viết lại các câu sau vào bài làm, bắt đầu bằng từ gợiý sao cho nghĩa không thay đổi so với câu ban đầu. 41. We can't celebrate a party this week. > We wish 42. The boy is too short to reach the shelf. → The boy isn't 43. People say that Ben En is a wonderful tourist attraction. → Ben En is 44. "Why don't we take a shortcut through the park?" Tim told me. > Tim suggested 45. She is the most hard-working student in your class, isn't she? > No one ? II. Viết lại các câu sau vào bài làm, sử dụng các từ cho sẵn để nghĩa của câu không thay đổi. Không biến đổi các từ cho sẵn. (FOR) 46. They started talking about their future 2 hours ago. > They have 47. If I were you, I would study harder to pass the exam. → You (SHOULD) 48. Ann was exhausted but she managed to finish her work in time. (AS) > Exhausted 49. Sarah refused Mike's invitation to his party. (TURNED) > Sarah 50. The information I got from the assistant was so confusing that I didn't know what to do. (SUCH) > The assistant provided -----The end-----
x + 4 + x + 6 +x +8 +x +.......+ x + 26 = 210
Câu 7: Sử cũ gọi chung cư dân thuộc văn hóa Đông Sơn là A. người Nam Việt. B. người Lạc Việt. C. người Đại Việt. D. người Bách Việt.
Look! A man ( run) after the train
Giúp mình câu này với ạ mình đang cần gấp
I. Supply the correct form of the words in bracket 1. The committee has made some ..........................changes for the better (DECIDE) 2. Do you know that the ..................of the awards are coming on Sunday? (RECEIVE) 3. She thinks chatting on the Internet is.......................(TIME-CONSUME) 4. John went to bed early because he had had a ___________day. (TIRE) 5. The professor explained his idea with great________. (CLEAR) II. Supply the correct form and tense of the verbs in brackets 1. You (stop) ______by a policeman if you try to cross the road now. 2. She wishes she (not give)______ them her phone number last week. 3. Would you be so kind as (switch off).............. the lights when leaving? 4. It's imperative that the wildlife program (broadcast)......... 5. Had it not been for her sickness, she (go out)................................ with me to the party
Mọi người ơi máy tính mình bị sao vậy ạ. Làm sao để nó trở lại bình thường.
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