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 

Mình cảm ơn 2 bn đã cho mk câu trả lời nhé ! Thaks you so much 

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.