a+b = 3+113=116

3 x |x| - 1/2 = 1/3

=> 3 x |x| = 5/6

=> x = 5/18

1/6 - 3 x |x+1| = 1/12

=> 3 x |x+1| = 1/12

=> |x + 1| = 1/36

x + 1 = 1/36 

=> x = -35/36

x  + 1 = -1/36

=> x = -37/36

Vậy x = -37/36 hoặc x = -35/36

Điền a/an/the hoặc nothing

1.Viet wants to send his letter to the USE

2.he lives in an L-shaped house in a town

3.last month we visited a very old church it's in the suburb of the city

4.i have a bad headache I'm going to see the doctor now

Tìm và sửa lỗi sai

41 We are going to have a two -week summer vacation in Hue next month

42 Long usually stays up late to do his homework

43 How many does it cost to send this letter to Chine?

44 My father has fewer days off than Tim's father

45 Sally knows how to keep fit. She never touches healthy food

46 Her father often listens to radio in the morning

47 I am hearing a bird now. It is singing

48 Jane is hungry to some chocolate ice - cream

Dung tu goi y

49 .Is it difficult to find an apartment in Ho Chi Minh City?

50.Who is the fattest person in your group?

54 . Would you like to go to the movies with me tonight?

dien tu thik hop

My name is peter and my ... usully begins at six thirty . I get up and do some ... for about fifteen minutes . Then I take my shower . After that I get dressed and have ... with my famili . At seven thirty I leave for school . I generally ... the bus to school . It takes about 20 minutes to ... to school . My forst class is at half past eight a I usually ... school at three . When I get ... I like to watch TV for a moment . Then I start my ... I have dinner at seven o'clock . After that ... often have more homework to do . I often go to ... at about a quarter to eleven

3S = 1.2.3 + 2.3.3+......+99.100.3

3S = 1.2.3 + 2.3.(4-1) +.......+99.100.(101-98)

3S = 1.2.3 +2.3.4-1.2.3+......+99.100.101 - 99.100.101

3S = (1.2.3-1.2.3) + (2.3.4-2.3.4) +...... + 99.100.101

3S = 99.100.101 =  999900

=> S = 333300 

Vậy S = 333300

Gọi số cần tìm là ab

Theo đề bài, ta có nếu ta đổi hai chữ số cho nhau thì đc số mới lớn hơn số cũ 54 đơn vị. Ta có PT:

ba - ab = 54

=> 10b + a - 10a -b = 54

=> 9b - 9a= 54

=> b - a = 6 (1)

Ta lại có b= 3a ( Vì hàng đơn vị gấp 3 làn hàng chục) (2)

Thay (2) vào (1)

=> 3a - a=6

=>a=3

=> b = 9

Vậy số càn tìm là 39.

Số chia hết cho 5 có tận cùng bằng 0;5.

Nhưng vì 25a3b chia hết cho 5.Suy ra b=5

Số chia hết cho 3 có tổng các chữ số chia hết cho 3.

Vậy 2+5+a+3+5=15+a=15;18;21; hoặc 24.

Vậy a chỉ có thể bằng: 0;3;6;9