C = 1 + 6 + 6²+ 6³+...+ 6¹⁰⁰

     6C =      6 + 6²+ 6³ +...+ 6¹⁰⁰ + 6¹⁰¹

6C - C =  6¹⁰¹ - 1

        5C = 6¹⁰¹ - 1

           C = \(\dfrac{6^{101}-1}{5}\)

\(C=1+6+6^2+...+6^{100}\)

\(\Rightarrow C=\dfrac{6^{100+1}-1}{6-1}\)

\(\Rightarrow C=\dfrac{6^{101}-1}{5}\)

1.telling

2.to see

3.taking

4.to smoke

5.to go

6.interrupting

7.having

8.to say

9.to go

10.being

1. telling → He delayed telling her the news, waiting for the right moment.
2. to see → I demand to see the manager.
3. to take → My father offered to take us to the airport.
4. smoking → I haven't missed smoking like I expected to.
5. going → We've had to postpone going to France because the children are ill.
6. to interrupt → I hate to interrupt, but it's time we left.
7. having → She admitted to having stolen the car.
8. to say → Katie chose to say away from work that day.
9. to go → Hurry up! We're waiting to go.
10. being → I don't appreciate being treated like a second-class citizen.

📌 Đáp án nhanh

1. telling
2. to see
3. to take
4. smoking
5. going
6. to interrupt
7. having
8. to say
9. to go
10. being

16-18+20-22+24-26+28-....-62+64-66+68

 = 16 +(20-18) + (24-22) + ( 28-26 ) +........+ (68-66)

 = 16 +2+2+2+.....+2

 = 16 + 2.26

 = 68

các phép tính trong ngoặc đều bằng 0 

suy ra chỉ còn 2005 +69 = 2074 
 

mày bị điên

a nhé mình ko chắc lắm

đâu phải chọn abc j đâu. mấy cái này là câu hỏi hết mà=/

Vì \(\frac{1}{13}+\frac{1}{14}+\frac{1}{15}<\frac{1}{12}+\frac{1}{12}+\frac{1}{12}=\frac{3}{12}=\frac{1}{4}\)

\(\frac{1}{61}+\frac{1}{62}+...+\frac{1}{66}<\frac{1}{60}+\frac{1}{60}+...+\frac{1}{60}=\frac{6}{60}=\frac{1}{10}\)

=> A < \(\frac{1}{3}+\frac{1}{4}+\frac{1}{10}=\frac{41}{60}<\frac{45}{60}=\frac{3}{4}\)điều phải c/m

là 177,8 nha bạn

    \(\left(57+58+59+60+61+62+63+64+65+66+67+68+69+70\right):5\)

\(=\left[\left(70+57\right).14:2\right]:5\)

\(=\left[127.14:2\right]:5\)

\(=1778:2:5\)

\(=889:5\)

\(=\frac{889}{5}\)

= 52 nha em

Chắc là 45 đọ