giúp mk với ak
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Answer:
a) 42% của 60kg
\(60\times42:100=25,2kg\)
b) 36,5% của 2ha
\(2\times36,5:100=0,73ha\)
TL:
Bài 1
a) 42% của 60 kg là :
60 : 100 x 42 = 25,2 kg
b) 36,5% của 2 ha là :
2 : 100 x 36,5 = 0,73 ha
a)\(\dfrac{87}{5}\)
b)\(6\)
c)\(\dfrac{224}{3}\)
d)\(\dfrac{31}{4}\)
1, The last shirt of this style was sold a few hours ago
2,,The Eiffiel was built in 1889
3,Rice is grown in tropical countries
4, This room is cleaned everyday
5, Our hands ,ust be washed before meal
6, You will be told what time the train leave by ur sis
7,A new bridge is going to be built in this area
8, He homework hasn't been done by her yet
9, Some friends of her have been asked to join us
11, I wish I knew many English words
12, I wish my friend could stay with me longer
13, I wish Lan were here
14, I wish I had a pen pal
15, I wish I could go to the soccer match that afternoon
16, She wishes she could speak English
1 saw - didn't see - was looking
2 met - went - went - had - were waiting
3 was cycling - stepped - was going - managed - didn't hit
4 was waiting - arrived
5 were you doing
6 Did you go
7 wore
8 were you driving - happened
9 took - wasn't looking
10 were - didn't know
Bài 1:
ĐKXĐ:
a. \(sinx\ne0\Rightarrow x\ne k\pi\)
b. \(sin2x\ne0\Rightarrow2x\ne k\pi\Rightarrow x\ne\dfrac{k\pi}{2}\)
c. \(cosx\ne0\Rightarrow x\ne\dfrac{\pi}{2}+k\pi\)
d. \(cos\left(x+\dfrac{\pi}{4}\right)\ne0\Rightarrow x+\dfrac{\pi}{4}\ne\dfrac{\pi}{2}+k\pi\Rightarrow x\ne\dfrac{\pi}{4}+k\pi\)
e. \(cos2x\ne0\Rightarrow2x\ne\dfrac{\pi}{2}+k\pi\Rightarrow x\ne\dfrac{\pi}{4}+\dfrac{k\pi}{2}\)
f. \(sin\left(x-\dfrac{\pi}{3}\right)\ne0\Rightarrow x-\dfrac{\pi}{3}\ne k\pi\Rightarrow x\ne\dfrac{\pi}{3}+k\pi\)
g. \(sinx+1\ge0\Rightarrow D=R\)
h. \(cosx-2\ne0\Rightarrow D=R\)
i. \(cosx-1\ne0\Rightarrow cosx\ne1\Rightarrow x\ne k2\pi\)
Bài 2:
a.
\(-1\le cosx\le1\Rightarrow-3\le3cosx\le3\Rightarrow-4\le y\le2\)
\(y_{min}=-4\) khi \(cosx=-1\)
\(y_{max}=2\) khi \(cosx=1\)
b.
\(-1\le sinx\le1\Rightarrow-1\le-sinx\le1\) \(\Rightarrow4\le y\le6\)
\(y_{min}=4\) khi \(sinx=1\)
\(y_{max}=6\) khi \(cosx=1\)
c.
\(0\le\sqrt{cosx}\le1\Rightarrow-3\le y\le-2\)
\(y_{min}=-3\) khi \(cosx=0\)
\(y_{max}=-2\) khi \(cosx=1\)
d.
\(0\le sin^2x\le1\Rightarrow2\le y\le3\)
\(y_{min}=2\) khi \(sinx=0\)
\(y_{max}=3\) khi \(sin^2x=1\Leftrightarrow cosx=0\)
1 2H2S + 3O2 \(\xrightarrow[]{t^o}\) 2SO2 + 2H2O
2 2H2O + 2KMnO4 + 5SO2 \(\xrightarrow[]{t^o}\) 2H2SO4 + 2MnSO4 + K2SO4
3 H2SO4 + Na2SO3 \(\rightarrow\) H2O + Na2SO4 + SO2
4 2C + SO2 \(\xrightarrow[]{t^o}\) 2CO + S
5 Fe + S \(\xrightarrow[]{t^o}\) FeS
6 H2SO4 +NaCl \(\rightarrow\) NaHSO4 + HCl
7 K2CO3 + 2NaHSO4 \(\rightarrow\) H2O + Na2SO4 + K2SO4+CO2
8 Na2SO4 + Ba(OH)2 \(\rightarrow\) 2NaOH + BaSO4
9 Br2 + H2O +SO2 \(\rightarrow\) H2SO4 + 2HBr
10 2HBr + Cl2 \(\rightarrow\) Br2 + 2HCl
I.
1D 2C 3A
II.
4D 5A 6C
III.
7B 8A 9A 10D 11D 12C 13C 14C 15A
IV.
16 explorer
17 dramatically
18 survival
19 challenging
20 unconscious
V.
21D 22B 23A 24C 25A
43. Not to spend so much money on magazines
44. Don't have to take part in the festival if you don't want to.
45. Was able to ride a bike when she was 5.
1 to work by car every morning
2 there 25 students in your class
3 quater past seven
4 is to the left of the drug store
5 small classroom
6 your school have
7 longer than the red river
1. to work by car every morning
2 .there 25 students in your class
3 .quater past seven
4 .is to the left of the drug store
5. small classroom
6 .your school have
7 .longer than the red river