Giúp toi với , cám ơn
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7: \(=\dfrac{x+7+x+x-7}{x\left(x+7\right)}=\dfrac{3x}{x\left(x+7\right)}=\dfrac{3}{x+7}\)
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23 Has Nga read
24 Have they played
25 Have - already washed
26 Is -travelling
7 makes
8 started
9 are - are playing
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1 had worked - went - is travelling
2 do you do - worked
3 had gone
4 got - had gone
5 met - hadn't seen
6 was making
7 is having
8 is making - makes
9 am wearing
10 is reading
11 borrows - remembers
12 is he doing - think - is polishing
13 saw - was painting
14 was reading
15 went
16 was discovered
17 drinks - drank
18 does she do - plays - watches
19 are waiting
20 had left
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7 friendly
8 traditionally
9 completely
10 compulsory
11 fashionab;e
12 modernized
13 friendly
14 convenient
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Phương trình hoành độ giao điểm là:
\(x^2-2x+m^2=0\)
Để (P) cắt (d) tại hai điểm nằm về hai phía trục tung thì \(m^2< 0\)
hay \(m\in\varnothing\)
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\(CuO+H_2\underrightarrow{^{t^0}}Cu+H_2O\)
=> Phản ứng thế
\(CaO+H_2O\rightarrow Ca\left(OH\right)_2\)
=> Phản ứng hóa hợp
\(Cu\left(OH\right)_2\underrightarrow{^{t^0}}CuO+H_2O\)
=> Phản ứng phân hủy
\(3Fe+2O_2\underrightarrow{^{t^0}}Fe_3O_4\)
=> Phản ứng hóa hợp
\(2KClO_3\underrightarrow{^{t^0}}2KCl+3O_2\)
=> Phản ứng phân hủy
\(Ba+2H_2O\rightarrow Ba\left(OH\right)_2+H_2\)
=> Phản ứng thế
\(Mg+2HCl\rightarrow MgCl_2+H_2\)
=> Phản ứng thế