1 She said if the weather was fine, she would go on a picnic with her friends

2 I asked him what he would do if he had three days off

3 She said to Jim she would have come to see him if she had known his address

4 He told me he was sure she would help me if I asked her

5 They told me if today was Sunday, they wouldn't go to school

6 She told me if she was me, she wouldn't tell her about that

7 She said there would not be enough seats if a lot of guest came

8 Peter told Linda she would be surprise if she met him

9 The boy said he wouldn't not be strong if he didn't swim everyday

10 Nam asked Nga what she would do if she saw a snake

1. She said that if the weather were fine she would go on a picnic with her friends

2. I asked him what he would do if he had three days off

3. She said that she would have come to see me if she had known my address

4. He told me that he was sure she would help me if I asked her

5. They told me that if that day were Sunday they wouldn't go to school

6. She advised me not to tell her about that

7. He/she/they said that there wouldn't be enough seats if a lot of guests came

8. Peter told Linda that she would be surprised if she met him

9. The boy said that he wouldn't be strong if he didn't swim everyday

10. Nam asked Nga what she would do if she saw a snake

1. She said that if the weather were fine she would go on a picnic with her friends.

2. I asked him what he would do if he had three days off..

3. She said that she would have come to see me if she had known my address.

4. He told me that he was sure she would help me if I asked her.

5. They told me that if that day were Sunday they wouldn't go to school.

6. She advised me not to tell her about that.

7. He/she/they said that there wouldn't be enough seats if a lot of guests came.

8. Peter told Linda that she would be surprised if she met him.

9. The boy said that he wouldn't be strong if he didn't swim everyday.

10. Nam asked Nga what she would do if she saw a snake.

b: =900x99=89100

C) 27.16+81.21+9.21.3

=432+1701+567

=2700

D)36.13+64.37+9.4.87+64.9.7

=468+2368+3132+4032

=10000

E) 2.14.98+7.4.32-28.30

=2744+896-840

=2800

I) 123.456+456.321-256.444

=56088+146357-113664

=88781

#NO COPY

#nho nekkk

I can how forget

I can how forget.

@YVHPokemon

k nhé

How can I forget?

Đúng 100%

Gọi số học sinh nam là x

Số học sinh nữ là 32-x

Vì khi chuyển 4 nữ đi thì số nam và số nữ bằng nhau nên ta có: 

32-x-4=x

=>28-x=x

=>x=14

Vậy: Có 14 nam và 18 nữ

Tôi yêu anh ấy nhưng anh ấy không còn nữa

Giải nghĩa : 

Tôi yêu anh ấy nhưng anh ấy không còn nữa

Tôi yêu anh ấy nhưng không còn nữa

14.

\(y'=2x^3-4x=2x\left(x^2-2\right)=0\Rightarrow\left[{}\begin{matrix}x=0\\x=-\sqrt{2}\\x=\sqrt{2}\end{matrix}\right.\)

\(y''=6x-4\)

\(\Rightarrow y''\left(0\right)=-4< 0\Rightarrow x=0\) là điểm cực đại

\(y\left(0\right)=-3\)

\(\Rightarrow\) Điểm cực đại của đồ thị hàm số là \(\left(0;-3\right)\)

12.

\(y'=3x^2-3=0\Rightarrow\left[{}\begin{matrix}x=1\\x=-1\end{matrix}\right.\)

\(y''=6x\)

\(\Rightarrow\left\{{}\begin{matrix}y''\left(1\right)=6>0\\y''\left(-1\right)=-6< 0\end{matrix}\right.\) \(\Rightarrow x=-1\) là điểm cực đại

\(\Rightarrow\)Giá trị cực đại của hàm số là \(y\left(-1\right)=3\)

2.

\(y'=x^2-2mx+m^2-m+1\)

\(y''=2x-2m\)

Hàm đạt cực đại tại \(x=1\) khi:

\(\left\{{}\begin{matrix}y'\left(1\right)=0\\y''\left(1\right)< 0\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}m^2-3m+2=0\\2-2m< 0\end{matrix}\right.\)

\(\Rightarrow\left\{{}\begin{matrix}\left[{}\begin{matrix}m=1\\m=2\end{matrix}\right.\\m>1\end{matrix}\right.\) \(\Rightarrow m=2\)

Tự luận 

Câu 1 : 

Trích mẫu thử

Cho $Ba(HCO_3)_2$ vào mẫu thử

- mẫu thử tạo khí không màu là $HCl$
$Ba(HCO_3)_2 + 2HCl \to BaCl_2 + 2CO_2 + 2H_2O$

- MT tạo kết tủa trắng là $Na_2SO_4$
$Ba(HCO_3)_2 + Na_2SO_4 \to BaSO_4 + 2NaHCO_3$

- MT tạo khí không màu và kết tủa trắng là $H_2SO_4$
$Ba(HCO_3)_2 + H_2SO_4 \to BaSO_4 + 2CO_2 + 2H_2O$

- MT không hiện tượng là $NaCl$

Câu 2 : 

$S + O_2 \xrightarrow{t^o} SO_2$
$2SO_2 + O_2 \xrightarrow{t^o} 2SO_3$
$SO_3 + H_2O \to H_2SO_4$
$NaCl + H_2SO_{4_{đặc}} \xrightarrow{t^o} NaHSO_4 + HCl$

Câu 3 : 

a) $2Al + 6HCl \to 2AlCl_3 + 3H_2$

$n_{HCl} = 0,1.3 = 0,3(mol)$

$n_{Al} = \dfrac{1}{3}n_{HCl} = 0,1(mol)$

$n_{H_2} = \dfrac{1}{2}n_{HCl} = 0,15(mol)$

Suy ra: 

$m = 0,1.27 = 2,7(gam)$
$V = 0,15.22,4 = 3,36(lít)$

Trắc nghiệm:

Câu 1: C

Câu 2: A

Câu 3: D

Câu 4: D
Câu 5: D

Câu 6: B

Câu 7: C 

Câu 8: B

Trắc nghiệm 

1.C    2.A    3.D     4.D     5.D     6.B và D    7.C   8B   

\(\frac{x}{2}\)= \(\frac{y}{3}\) =\(\frac{z}{4}\)và x +  2y  +  3z  = -20

Áp dụng tính chất dãy tỉ số bằng nhau ta có :

\(\frac{x}{2}\)=\(\frac{y}{3}\)=\(\frac{z}{4}\)= \(\frac{x+2y+3z}{2+6+12}\)= \(\frac{-20}{20}\)= -1

\(\frac{x}{2}\)= -1  => x = (-1)  .  2  =  -2

\(\frac{y}{3}\)= -1 =>  y = (-1)  .  3  =  -3

\(\frac{z}{4}\)=  -1  => z = (-1)  .  4 =  -4

Vậy x = -2  ,  y= -3    z= -4

thank bạn