\(x-\frac{1}{2}-\frac{1}{6}-\frac{1}{12}-...-\frac{1}{9900}=7,5\)

\(x-\left(\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+...+\frac{1}{9900}\right)=7,5\)

\(x-\left(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+...+\frac{1}{99.100}\right)=7,5\)

\(x-\left(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{99}-\frac{1}{100}\right)=7,5\)

\(x-\left(1-\frac{1}{100}\right)=7,5\)

\(x-\frac{99}{100}=7,5\)

\(\Rightarrow x=7,5+\frac{99}{100}=\frac{750}{100}+\frac{99}{100}\)

\(\Rightarrow x=\frac{849}{100}=8,49\)

Dấu "." là dấu nhân nha bạn

80 + 9 = 89 

Tích tớ nha 

chu vi 40m

38. Yesterday (be) __________ a beautiful day. The Sun (shine) ____________________ brightly when we
(leave) ______________ home.
39. The teacher asked me if I (know) __________ where the Statue of Liberty was.
40. Listen! Mai (play) ____________________ the piano in her room.
41. + What kind of music ____________ you (like) __________ ?
+ I like pop music.
42. In summer, the Sun usually (shine) __________________ brightly.
43. I (not finish) _______________________ reading the novel you lent me yet.
44. Julia (write) ________________________ an email to her boy friend now.
45. Jack (not meet) _______________________ Tom the last time he came to America.38. Yesterday (be) __________ a beautiful day. The Sun (shine) ____________________ brightly when we
(leave) ______________ home.
39. The teacher asked me if I (know) __________ where the Statue of Liberty was.
40. Listen! Mai (play) ____________________ the piano in her room.
41. + What kind of music ____________ you (like) __________ ?
+ I like pop music.
42. In summer, the Sun usually (shine) __________________ brightly.
43. I (not finish) _______________________ reading the novel you lent me yet.
44. Julia (write) ________________________ an email to her boy friend now.
45. Jack (not meet) _______________________ Tom the last time he came to America.

rewrite sentences using passive voice
1, did your father repair your bicycle yesterday?
2, does your teacher often ask you to give speeches
3, nobody gave me a birthday present on my last birthday
4, did they elect Nam as a President of the club
5, were you feeding the birds in your garden at three o'clock yesterday afternoon?
6, they were repairing the cả when the accident happened
7, many women are now taking over business for their absent husbands
8, did they finish the work?
9, will they holg the meeting before the first of may
10,someone was claening the windown while i was there