`@` `\text {Ans}`

`\downarrow`

mờ qué mik ko nhìn dc

 

a) Diện tích tam giác ABC là:

7.2 ✖ 7.5 = 54 ( cm²)

b) S_APQ / S_ABQ = AP / AB = 1 / 3

S_ABQ / S_ABC = AQ / AC = 1 / 4

S_APQ / S_ABC = 1 / 3 ✖ 1 / 4 = 1 / 12

Vậy S_APQ chiếm 1 phần và S_ABC chiếm 12 phần

Diện tích tam giác APQ là:

 54 : 12 = 4.5 ( cm² )

Chúc bạn học tốt nha

Bài 6:

\(A=3+\left(3^2+3^3\right)+\left(3^4+3^5\right)+...+\left(3^{2020}+3^{2021}\right)\\ A=3+3^2\left(1+3\right)+3^4\left(1+3\right)+...+3^{2021}\left(1+3\right)\\ A=3+4\left(3^2+3^4+...+3^{2021}\right)⋮̸4\left(3⋮̸4\right)\)

Bạn chụp lại đề nha bạn

VI

1 I used to spend hours playing with doll when I was a child

2 He ought to go to the dentist

3 Why were you late for school yesterday

4 I used to live on a farm

5 Nga is interested in listening to traditional stories

6 I asked Sara to drive me to the bus station

Tham khảo

Ta có: \(n_{CH_3COOH}=\dfrac{60}{60}=1\left(mol\right)\)

a, PT: \(2CH_3COOH+K_2CO_3\rightarrow2CH_3COOK+CO_2+H_2O\)

_________1____________________1_________0,5 (mol)

b, V_CO2 = 0,5.22,4 = 11,2 (l)

c, m_CH3COOK = 1.98 = 98 (g)

Bạn tham khảo nhé!

a) PTHH:         2CH₃COOH + K₂CO₃ → 2CH₃COOK + CO₂↑ + H₂O

b) n_CH3COOH = \(\dfrac{m}{M}=\dfrac{60}{60}=1\left(mol\right)\)

Theo PTHH: n_CO2 = \(\dfrac{1}{2}\).n_CH3COOH = 0,5 (mol)

=> V_{CO2 (đktc)} = n.22,4 = 0,5.22,4 = 11,2 (lít)

c) Theo PTHH: n_CH3COOK = n_CH3COOH = 1 (mol)

=> m_CH3COOK = n.M = 1.98 = 98 (g)

Mặc dù hơi muộn nhưng mà chúc bạn thi đạt kết quả tốt nha ^_^

A 

1 A

2 C

3 C

4 D

B

1 F

2 T

3 F

4 T

My mother used to work at a restaurant 3 years ago but now she doesn't

He used to be the president of Student Union but now he isn't

There used to be many trees - lined in my hometown but now there is none of them

My husband didn't use to do homework but now he does

Children didn't use to play with high-tech devices at an early age

1. My mom used to work at a restaurant

2. He used to be the president of Student Union

3. There used to be many tree-lined street in my hometown.

4. My husband didn't use to do the housework.

5. The children didn't use to play with high-tech devices.

My mother used to work at  restaurant three years ago.

 He used to be the president of Student Union.

There used to be many tree-lined streets in my hometown.

My husband didn't use to do  housework.

childrent didn't use to play with high-tech devices at an early age.