Đáp án + Giải thích các bước giải:
`1)`
`3x(x-2)-x(1+3x)=14`
`<=> 3x^2-6x-x-3x^2=14`
`<=> -7x=14`
`<=> x=-2`
Vậy `x=-2`
`2)`
`2x(x+3)-3(x^2+1)=x+1-x(x-2)`
`<=> 2x^2+6x-3x^2-3=x+1-x^2+2x`
`<=> 2x^2-3x^2+x^2+6x-x-2x=1+3`
`<=> 3x=4`
`<=> x=4/3`
Vậy `x=4/3`
`3x(x-2) -x(1+3x) =14`
`-> 3x^2 - 6x - x - 3x^2 = 14`
`-> -7x =14`
`-> x = -2`
Vậy `x =-2`
$\\$
`2x(x+3) -3(x^2+1) = x+1 -x(x-2)`
`-> 2x^2+6x - 3x^2 -3 = x+1 - x^2 +2x`
`-> -x^2 +6x -3 = x + 1 - x^2+2x`
`-> -x^2 + x^2 - 3 -1 = x - 6x + 2x`
`-> -4 =-3x`
`-> x = 4/3`
Vậy `x =4/3`
IV. Put the verbs in correct tenses. 1. …………………..You (wait) ………………………for her when her plane arrives tonight? 2. Don’t phone me between 7 and 8. We (have) ………………….………….. dinner then. 3. I (send) ………………….………….. you my book tomorrow. 5. We hope the new Director (find) ………………….………….. more jobs for his employees. 6. Nam is a hard-working student. He (pass) ……………….…………. the exam easily this year. 6. What …………………..you (do) ………………….. when you graduate from the University? 7. Next week we (have) ……………..……… many kinds of examinations. It (be) ………….… a very busy week, I think. 8. In the future, most of Vietnamese people (be able) …..……. (speak) ……………English well. 9. Next week at this time, you (lie) ………………….………….. on the beach. 10. …………………..You (meet) …………………..your former teacher at 9 am tomorrow? giúp
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III. Rewrite the second sentences, keeping the meaning unchanged: 1. They will use solar energy to protect the environment. -> Solar energy ………………………………………………………………….. 2. Although she eats lots of food, she is still very slim. ->In spite of ………………………………………………………………….. 3. What is the distance between Hanoi and HCM city? -> How far …………………………………………………………………..? 4. Although she is so young, she sings beautifully (age) -> In spite of ………………………………………………………………….. 5. I find English interesting. -> I am …………………………………………………..… 6. Our roof will be fixed tomorrow. -> They…………………………………………………….. 7. They will show flying cars to the public when they finish it. -> Flying cars …………………………………………………………………….. 8. They will install solar panels on the roof of our house next week. -> Solar panels …………………………………………………………………………………… 9. We will be using biogas for cooking and heating at this time next month. -> Biogas ……………………………………………………………………………………………... 10. People won’t burn fossil fuels for energy in the future. -> Fossil fuels …………………………………………………………………………………… Giúp mình nhanh nhé
Bạn nào làm nhanh đúng vote 5 sao
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II. Choose and circle the best answer. 1. Many ……………. (cultural/ romance/ disappointed/ annoyed) and artistic activities are held as the part of the flower festival in Da Lat. 2. Wind, hydro and solar are ………. (modern/ renewable/ non-renewable/ new) energy sources. 3. Nick washes his hand a lot, (so/ and/ but/ although) he doesn’t have flu. 4. At a seasonal festival, people race down the hill to (break/ catch/ buy/ eat) cheese. 5. (When/ How/ Why/ Where) were you born? – In March 6. We will cut down on the use of natural gas because it is …….… & harmful to the environment. A. plenty B. limited C. available D. abundant 7. Which of the following is NOT non-renewable source of energy ? A. oil B. wind C. natural gas D. coal 8. Some new energy-saving bulbs …………. in the dining-room. A. will put B. will be putting C. will be put D. will being put Help me
Giúp em bài 3 ạ Xong em vote 5 sao và ctlhn ạ
Ai giúp mình với 🥺. Hứa sẽ ❤️ và votes ạ
I. Choose the word having different stress from the others. 1. A. harvest B. parade C. music D. pumpkin 2. A. offer B. prefer C. abroad D. arrive 3. A. famous B. joyful C. usual D. alone 4. A. exist B. avoid C. support D. notice 5. A. hungry B. disease C. spacious D. danger 6. A. favourite B. pollution C. imagine D. exhausted 7. A. energy B. plentiful C. disappear D. celebrate 8. A. recycle B. description C. contribute D. atmosphere Giúp mình nhanh nhé mn, nhớ kèm giải thích
Giải phương trình nghiệm nguyên: `2^x +2^y+2^z=2^n (n in ZZ, x ≤y ≤z)`
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