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\(\dfrac{x}{3}-\dfrac{1}{2}=\dfrac{1}{5}\)
\(\dfrac{x}{3}=\dfrac{1}{5}+\dfrac{1}{2}\)
\(\dfrac{x}{3}=\dfrac{7}{10}\)
\(10x=21\)
\(x=2,1\)


1 haven't cleaned
2 will be
3 is sleeping - gets
4 is teaching
5 does - isn't going - is watching
6 have written
7 hadn't disturbed
8 have you worked
9 get - get
6 studies - are trying
7 had stood
8 drove
9 have you studied
10 have waited - hasn't come
11 have lived


/ -2 / = 2x + 3
\(=>2=2x+3\)
\(=>-1=2x\)
\(=>-2x=1\)
\(=>x=\frac{-1}{2}\)
Ủng hộ mik nha

-12.(x-5)+7.(3-x)=5
-12x-60+21-7x=5
(-12x-7x)-(60+21)=5
-19x-81=5
-19x=5-81
-19x=-76
x=-76:(-19)
x=4
x=
x=44:(-19)
\(-12\left(x-5\right)+7\left(3-x\right)=5\)
\(60-12x+21-7x=5\)
\(81-19x=5\)
\(19x=81-5\)
\(19x=76\)
\(x=4\)

Ta có: \(n_{CH_3COOH}=\dfrac{60}{60}=1\left(mol\right)\)
a, PT: \(2CH_3COOH+K_2CO_3\rightarrow2CH_3COOK+CO_2+H_2O\)
_________1____________________1_________0,5 (mol)
b, VCO2 = 0,5.22,4 = 11,2 (l)
c, mCH3COOK = 1.98 = 98 (g)
Bạn tham khảo nhé!
a) PTHH: 2CH3COOH + K2CO3 → 2CH3COOK + CO2↑ + H2O
b) nCH3COOH = \(\dfrac{m}{M}=\dfrac{60}{60}=1\left(mol\right)\)
Theo PTHH: nCO2 = \(\dfrac{1}{2}\).nCH3COOH = 0,5 (mol)
=> VCO2 (đktc) = n.22,4 = 0,5.22,4 = 11,2 (lít)
c) Theo PTHH: nCH3COOK = nCH3COOH = 1 (mol)
=> mCH3COOK = n.M = 1.98 = 98 (g)
Mặc dù hơi muộn nhưng mà chúc bạn thi đạt kết quả tốt nha ^_^
Đề số 2:
I.
1. B go
2. A little
3. A I am never late for school
4. B of / at
5. C good
6. B celebrate
7. C taking
8. A buys
9. A more
10. C what
II.
1. does / watches
2. is being / will be
3. see / play
4. to listen / to read
III. (không thấy phần gạch)
IV.
1. The black dress is more expensive than the green dress.
2. What about coming to my house after school?
3. Mr Lam drinks less coffee than Mr Tam
4. What is your the birthday's date?