Đáp án:
Giải thích các bước giải:
`30/{x+10} + 30/{x-6} = 60/x` (ĐKXĐ: `x\ne-10; 6; 0`)
`<=> 30(1/{x+10} + 1/{x-6}) = 60/x`
`<=>1/{x+10} + 1/{x-6} = 2/x`
`<=>{(x-6)x}/{x(x+10)(x-6)} + {(x+10)x}/{(x-6)(x+10)x} = {2(x+10)(x-6)}/{(x-6)(x+10)x}`
`<=>{x^2 - 6x + x^2 + 10x - 2 (x^2 + 4x - 60)}/{(x-6)(x+10)x} =0`
`=> 2x^2 + 4x - 2x^2 - 8x + 120=0`
`<=> -4x+120=0`
`<=> -4x=-120`
`<=>x =30(tmdk)`
Vậy `x=30.`
$\begin{array}{l}\dfrac{30}{x+10}+\dfrac{30}{x-6}=\dfrac{60}{x}\text{ (ĐK:$x\neq\{-10;0;6\}$)}\\⇒\dfrac{30x(x-6)}{x(x+10)(x-6)}+\dfrac{30x(x+10)}{x(x+10)(x-6)}=\dfrac{60(x-6)(x+10)}{x(x+10)(x-6)}\\⇒30x^2-180x+30x^2+300x=60(x^2+4x-60)\\⇒60x^2+120x=60x^2+240x-3600\\⇒120x=240x-3600\\⇒120x=3600\\⇒x=30_\text{(tm)}\end{array}$
Vậy $x=30$
x+16 x+18 x+20 ------- + -------- = ------- + 1 49 47 45
(2m-1)x²+(4m-2)x-m ≥120 Mời các chuyên toán xơi ạ !!!!!!!!!!!!!!!! (giải bất phương trình chứa m)
II. PHONETICS: Choose the word that has the underlined part pronounced differently from the others (1m) 1. a. theatre b. Thanksgiving c. weatherman d. earth 2. a. near b. team c. year d. idea 3. a. favourite b. fine c. high d. nice 4. a. cold b. old c. snow d. popular III. VOCABULARY AND GRAMMAR A. Choose the best answer (2,5ms) 1. My brother likes watching TV……………….. I like going out with my friends. a. and b. but c. because d. so 2. ………….. is a man on television or on the radio who gives a weather forecast. a. MC b. Newsreader c. Viewer d. Weatherman 3. The Nobel Prize is …………. in Stockholm every year. a. done b. sent c. awarded d. written 4. ………….. bring a lot of laughter and help people relax after working hard. a. Comedies b. Game shows c. News d. Films 5. They……………………. to London twice. a. were b. has been c. are d. have been 6. Because it doesn’t snow in Viet Nam, we can not ………… skiing. a. go b. do c. play d. run 7. Hoa ……….. volleyball with her friends yesterday. a. play b. played c. to play d. plays 8. …………… became well-known around the world as “The King of football”. a. Rooney b. Ronaldo c. Pelé d. Messi B. Match the questions in column A with the answers in column B (1m) A B 1. What is your favourite TV programme? 2. Have you ever been to Singapore? 3. When is the show on? 4. Why should people exercise? a. Because it can help them be healthy b. I like watching sports. c. At 8.30 Saturday evening. d. Yes, I’ve been there twice. 1. … 2. … 3. … 4. … IV. READING A. Use the words in the box to complete the postcard (1m) beautiful delicious but weather people Hi Nick, Hue is a great city. The (1)……………… is fine. It’s sunny all the time. The food is cheap and (2)………………… The (3)……………… here are friendly and hospitable. The hotel where we’re staying is small (4)……………. comfortable. Tomorrow we’re going on a trip along the Huong river. You must visit this city someday. You’ll love it. Bye for now! Cheers, Mi B. Read the passage then answer the questions (1m) Seoul is South Korea’s capital. It is located in the northern part of South Korea. It has a population of nearly 10 million people. In this city you can find many tall buildings and skyscrapers. Seoul is known around the world as a technology capital. It has a large subway system. Incheon International Airport is a forty minute train ride from Seoul. Gangnam, Itaewon and Hongdae are popular neighbourhoods in Seoul. The War Memorial of Korea and Namsan Seoul Tower are popular tourist destinations in Seoul. 1. Where is Seoul?-->………………………………………………………………... 2. How many people live in Seoul?-->……………………………………………… 3. Is Seoul a technology capital?-->………………………………………………… 4. How long does it take to travel from Seoul to Incheon Airport by train? ……………………………………………………………………………………... V. WRITING A. Rearrange the words to make the sentences (1m) 1. VTV1/ a national television /is / in Viet Nam ……………………………………………………………………………………. 2. are there / How many/ players /a football match/ in ? ……………………………………………………………………………………. 3. We / yesterday/ the Temple of Literature/ visited/. ……………………………………………………………………………………. 4. in France / building /The Eiffel Tower /is /the most famous/ ……………………………………………………………………………………. B. Rewrite the sentences (1m) 1. Nga likes table tennis most. Nga’s favourite ……………………………………..………………………………. 2. You don’t want your friend to tell anyone about this. You say: “ Please ………………………………….……………….……………… 3. We turned to the Movie Channel. We wanted to watch Pinocchio. (Because) ……………………………………………………………………………………….. 4. Minh goes to the karate club three times a week. ( Make questions for underlined part) ………………………………………………………………………………………..
dựa vào đoạn trích từ '' chị Thao cầm cái thước... tôi sẽ giải quyết hết '' ,( sgk/116,117). Em hãy nêu cảm nhận của mình về nhân vật Phương Định
cho tam giác ABC cân tại a kẻ BD vuông góc với AC và ck vuông góc với AB (H thuộc AC K thuộc AB) BH BH cắt CK tại E a) chứng minh AH = AK b) chứng minh AE là tia phân giác của góc BAC c) trên nửa mặt phẳng bờ BC không chứa điểm a lấy điểm m sao cho BM = MC chứng minh ba điểm A,E,M thằng hàng Làm nhanh giúp mình
$\left \{ {{x+y=1} \atop {x^2+xy+y^2=7}} \right.$
Lập dàn ý viết cảm nghĩ về nhân vật thầy Ha-men trong văn bản "Buổi học cuối cùng". Các bn lm hộ mk với! Mk cảm ơn nhìu lắm ạk!
làm giúp mk bài trải nghiệm sáng tạo : ' nếu tôi là nhà văn ' ?
Các đại lượng hoặc tính chất sau đây của kim loại kiềm thổ biến đổi như thế nào khi diện tích hạt nhân nguyên tử tăng dần? a. Bán kính nguyên tử b. Năng lượng ion hóa c. Thế điện cực chuẩn Eo d. Tính khử.
• For questions 1 - 7, read the three texts below and decide which answer (A, B, c, or D) best fits each gap: This book began when I (1) ............. a suggestion to try my hand as a political journalist nine years ago. What makes this (2) ............. so wonderfully bearable is that unfashionable as it now is to say so, I'm rather fond of British Members of Parliament. They can be dreadfully silly, of course, and there are days when they irritate (3) ............. measure. Occasionally, even, comes a moment when an MP's speech or behavior (4) ............. genuine anger, goading me into an attempt at lofty (5) ............. But I always regret it. It rarely reads well the next day. There are other journalists to ride high horses and my mission, I think, is to remind readers that their MPs are often more (6) ............. than they are wicked and that, through the laughter, we may discern the outlines of arguments, ambitions, even principles. MPs are mostly human, rarely scaling the heights nor often touching the depths to (7) ............. the famous figures of history fly. Only a handful among them are of unusual intelligence but many are effective and most are hard-working. 1, A. agreeable B. approved C. accepted D. agreed 2, A. slavery B. servitude C. maid D. charwoman 3, A. far off B. yonder C. further on D. beyond 4, A. arouses B. awake C. set off D. enkindle 5, A. condemnation B. condemn C. self-condemnation D. admonition 6, A. ludicrous B. ridiculous C. laughable D. outrageous 7, A. whichever B. whose C. whomsoever D. which
Loga.vn - Cộng Đồng Luyện Thi Trực Tuyến
