a:Mg +2HCL---->MGCL2+ H2O

a. Mg + 2HCl ---> MgCl₂ + H₂↑

b. Fe₂O₃ + 6HCl ---> 2FeCl₃ + 3H₂O

c. 2Al + 6HCl ---> 2AlCl₃ + 3H₂↑

d. 2C₂H₆ + 7O₂ ---t^o---> 4CO₂↑ + 6H₂O

e. BaCl₂ + 2AgNO₃ ---> Ba(NO₃)₂ + 2AgCl↓

f. Al₂(SO₄)₃ + 3Ba(OH)₂ ---> 2Al(OH)₃ + 3BaSO₄↓

Trong đó:

t^o: nhiệt độ

↑: bay hơi

↓: kết tủa

(Câu f sai nên mik sửa từ Al₂(SO₄)₃ thành Al(OH)₃)

1 F

2 T

3 T

4 T

5 F

6 F

1 F

2 T

3 T

4 T

5 F

6 F

III

1 appreciated

2 worried

3 tense

4 confident

5 delighted

6 frustrated

7 calm

8 relaxed

9 self-disciplined

10 depressed

V

1 had resolved

2 has taken

3 Did you say

4 not to take

5 wanted

6 is being repaired

7 taking

8 to think

9 had worked

10 was washing - dropped

11 will find

12 faces

13 turned

14 to give

15 will empathise

Đặt \(A=\dfrac{1}{\sqrt[3]{a+7b}}+\dfrac{1}{\sqrt[3]{b+7c}}+\dfrac{1}{\sqrt[3]{c+7a}}\)

\(A=\dfrac{\sqrt[3]{64}}{\sqrt[3]{8.8\left(a+7b\right)}}+\dfrac{\sqrt[3]{64}}{\sqrt[3]{8.8\left(b+7c\right)}}+\dfrac{\sqrt[3]{64}}{\sqrt[3]{8.8\left(c+7a\right)}}\)

\(\ge\dfrac{4}{\dfrac{8+8+a+7b}{3}}+\dfrac{4}{\dfrac{8+8+b+7c}{3}}+\dfrac{4}{\dfrac{8+8+c+7a}{3}}\ge\dfrac{\left(2+2+2\right)^2}{\dfrac{8+8+a+7b+8+8+b+7c+8+8+c+7a}{3}}\)

\(=\dfrac{36.3}{8\left(a+b+c\right)+48}=\dfrac{3}{2}\)

Vậy \(A_{min}=\dfrac{3}{2}\Leftrightarrow a=b=c=1\)

4, were

5, was

6, were

7, was

8, were

9, was

10, were

11, were

12, was

13, was

14, was

4.was

5.was

6.were

7.was

8.were

9.was

10.were

11.were

12.was

13.was

14.was

Câu 4:

\(\dfrac{25}{26}-\dfrac{15}{26}=\dfrac{5}{13}\)

\(\dfrac{46}{39}-\dfrac{11}{13}=\dfrac{1}{3}\)

\(\dfrac{37}{45}-\dfrac{5}{9}=\dfrac{4}{15}\)

\(1-\dfrac{1}{3}=\dfrac{2}{3}\)

Câu 5:

Cạnh ngắn là:

\(2-\dfrac{1}{3}=\dfrac{5}{3}\left(m\right)\)

Chu vi hình bình hành là:

\(\left(2+\dfrac{5}{3}\right)\times2=\dfrac{22}{3}\left(m\right)\)

Nửa chu vi hình bình hành là:

\(\dfrac{22}{3}:2=\dfrac{11}{3}\left(m\right)\)

Chọn D

Phương trình \(\Delta\) có dạng:

\(y=m\left(x+1\right)-2\Leftrightarrow y=mx+m-2\)

Phương trình hoành độ giao điểm (P) và \(\Delta\):

\(-\dfrac{1}{2}x^2=mx+m-2\Leftrightarrow x^2+2mx+2m-4=0\) (1)

\(\Delta'=m^2-2m+4=\left(m-1\right)^2+3>0\) ; \(\forall m\)

\(\Rightarrow\) (1) luôn có 2 nghiệm pb với mọi m hay (P) luôn cắt \(\Delta\) tại 2 điểm pb

b.

Theo hệ thức Viet: \(\left\{{}\begin{matrix}x_A+x_B=-2m\\x_Ax_B=2m-4\end{matrix}\right.\)

Đặt \(A=x_A^2x_B+x_Ax_B^2=x_Ax_B\left(x_A+x_B\right)\)

\(A=-2m\left(2m-4\right)=-4m^2+8m=-4\left(m-1\right)^2+4\le4\)

\(A_{max}=4\) khi \(m=1\)