Đáp án:
Giải thích các bước giải:
$(x+1)(x-2)<0$
$⇔\left[ \begin{array}{1}\left\{ \begin{matrix}x+1>0\\x-2<0\end{matrix} \right.\\\left\{ \begin{matrix}x+1<0\\x-2>0\end{matrix} \right.\end{array} \right.$
$⇔\left[ \begin{array}{1}\left\{ \begin{matrix}x>-1\\x<2\end{matrix} \right.\\\left\{ \begin{matrix}x<-1\\x>2\end{matrix} \right.\end{array} \right.$
$⇔\left[ \begin{array}{1}-1<x<2\\2<x<-1\end{array} \right. (L)$
$⇒-1<x<2$
Đáp án: ` -1 < x < 2`
`(x + 1)(x - 2) < 0`
Xét `2 TH`
- \(\left\{ \begin{array}{l}x + 1 > 0\\x - 2 < 0\end{array} \right.\)
`<=>` \(\left\{ \begin{array}{l}x > -1\\x < 2\end{array} \right.\)
`<=> -1 < x < 2`
- \(\left\{ \begin{array}{l}x + 1 < 0\\x - 2 > 0\end{array} \right.\)
`<=>` \(\left\{ \begin{array}{l}x < -1\\x > 2\end{array} \right.\)
`=> loại`
xin lỗi cho em hỏi câu 2 và câu 3 trong Phần IV được ko ạ
1. You (be)____________ free tomorrow afternoon? 2. What your sister usually (do)____________ in her free time? She usually (watch) ____________TV, but sometimes she (listen) _________to music. 3. We (complete) _____________our project tonight. 4. I (go)_____________ to the Art Club every weekend. 5. Last Sunday, Minh (visit)___________ his uncle. He (be) ____________there for three hours. 6. New Zealand ( be)______________ divided into the North island and the South island. 7. America ( celebrate)____________ Thanksgiving Day on the fouth Thursdady of November. 8. England , Scotland, Wales , and Northern Island together ( form)______________ the United Kingdom. 9. The state of Liberty in New York is a monument ( symbolise)__________________ freedom. 10. There are about 750 million English speakers in the world, and this number (increase)_________________ fast. 11. It ______________everyday last week.(rain) 12. They ___________________down the street when it began to rain. (go) 13. At this time last year, I ___________________an English course.(attend) 14. They _______________a class meeting at 8 o’clock tomorrow morning. (have) 15. The boy fell and hurt himself while he _________________ a bicycle. (ride) 16. I ________________ (call) Mr Wilson at 9 last night, but he (not be)_________________at home. He (study) _______________ at the library. 17. I _________________ (not hear) the thunder during the storm last night because I ________________ (sleep) 18. It was beautiful yesterday when we went for a walk in the park. The sun______________(shine). The birds_____________(sing) 19. My brother and sister ________________ (talk) about something when I ________________ (walk) into the room 20. I _______________(be) looking for some photos when you rang but I ______________(not find) them 21. He’s on the holiday at that moment. He (go)______________ to Spain 22. I ___________________ English since 1976 (teach) 23. I __________________ a letter a few minutes ago (receive) 24. They ________________ in London since 1980 (live) 25. Linda is working in this department. She ______________________ here for two years (work) 26. Up to the present, John ___________________ good work in the class (do) 27. Now we_________________an old pagoda in Hoi An. (visit) 28. You _______________ your book on my desk last night (put) 29. He _________________ English at this school for six weeks up to now (study) 30. Our present teacher ________________ in this city all of his life (live)
Bài 5 và 6 làm hết nha đừng nhìn bài mik làm dở nó sai hết nha
Helpppp me:((((((( Sắp phải nộp r mà lười quáaaaaa
Mọi người giúp e với ạ!! Cảm ơn mọi người nhiều lém!!
Tại sao sự chênh lệch nhiệt độ giữa ngày và đêm lại tới hơn 10 độ C
sục v lít co2 vào 100ml dung dịch ca(oh)2 có nồng độ a(M) 2 gam kết tủa . tính giá trị của A giups với ạ
viết pt hoá học sau nếu có: K+h2o Cu+h2o Hcl+ba(oh)2 H2so4+caco3 Fe+h2so4 Cu+agno3 Na2co3+ba(oh)2 Naoh+cucl2 Fe(oh)3 Hcl+agno3 Cao+so2 Zn+cucl2 Koh+fecl3 Na2so4+ba(no3)2
Giúp mình câu tìm max, min này với ạ
Tính giá trị biểu thức A với x= 999 A= $x^{6}$- $x^{5}$ .(x-1)- $x^{4}$ .(x-1)+ $x^{3}$. (x-1)+ $x^{2}$ .(x-1)- x .(x-1)+ 1
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