\(n_{Fe_3O_4}=\dfrac{8}{232}=\dfrac{1}{29}\left(mol\right)\)

\(Fe_3O_4+8HCl\rightarrow FeCl_2+2FeCl_3+4H_2O\)

\(\dfrac{1}{29}.......\dfrac{8}{29}................\dfrac{2}{29}\)

\(m_{HCl}=\dfrac{8}{29}\cdot36.5=10.06\left(g\right)\)

\(m_{FeCl_3}=\dfrac{2}{29}\cdot162.5=11.21\left(g\right)\)

\(i=i'\)

\(\Rightarrow i'=30^o\)

a) \(\dfrac{3}{4}+\dfrac{9}{5}\div\dfrac{3}{2}-1=\dfrac{3}{4}+\dfrac{18}{15}-1=\dfrac{39}{20}-1=\dfrac{19}{20}\)

b) \(\dfrac{6}{7}\cdot\dfrac{8}{13}+\dfrac{6}{13}\cdot\dfrac{9}{7}-\dfrac{4}{13}\cdot\dfrac{6}{7}=\dfrac{48}{91}+\dfrac{54}{91}-\dfrac{24}{91}=\dfrac{48+51-24}{91}=\dfrac{78}{91}=\dfrac{6}{7}\)

c) \(\dfrac{-3}{7}+\left(\dfrac{3}{-7}-\dfrac{3}{-5}\right)\)\(=\dfrac{-3}{7}+\left(\dfrac{-3}{7}-\dfrac{-3}{5}\right)=\dfrac{-3}{7}+\dfrac{6}{35}=-\dfrac{9}{35}\)

ờ...tớ ko nhầm thì thừa are

nếu bỏ are thì she's making a papper boat

Bỏ are, she's making a paper boat

có 2 từ She

1 How long do you live in HN

2 How often did you go to the movies

3 What did Mrs Robinson buy

4 When was your father in Nghe An

5 How do they go to school

6 Why didn't she go to class

7 Who left home at 7o'clock yesterday

8 What subject does he study in the high school

9 What is your favorite hobby

10 How far is it

3. are there any eggs?-No, there aren't some

4.is there any salt?- yes, there is any

5.are there any carrots?-yes, there are some

6.are there any apples?-no there aren't some

7.is there any suger?-yes, there is any

8.are there any cakes?-no there aren't some

9.is there any butter?-no. there isn't any

10. is there any mineral water?- yes. there is any

chậm chạp

yếu ớt

mềm

cong

sáng

a) Chậm chạp, từ từ

b) Cao lớn, to cao

c) Mềm

d) Cong

e) Sáng

a/ Chậm chạp

b/ Yếu ớt

c/ Mềm

d/ Cong

e/ Sáng

1. excited           2. classmates                 3. uniforms               4. creative - creatively                5. boarding           6. international

7. equipment             8. library

VI. 

be excited about: thích thú điều gì

put on: mặc cái gì vào

3. on + ngày cụ thể

4. at

5. In 

4) Xét \(\Delta ADB\) và \(\Delta ADE\) có:

AB=AE

\(\widehat{A_1}=\widehat{A_2}\)  

AD chung

Vậy \(\Delta ADB=\Delta ADE\left(c.g.c\right)\) 

\(\Rightarrow DB=DE\left(2.cạnh.tương.ứng\right)\)

Giúp mình câu 4 nha

- Xét tam giác ABD và tam giác ADE có:

Góc A₁=Góc A₂ (AD là phân giác góc BAC)

AB=AE (gt)

AD là cạnh chung.

=> Tam giác ABD= Tam giác ABE (c-g-c)

=>AD=DE (2 cạnh tương ứng).