sorry tui làm sai câu này!!!

2/3 +4/37 +5/111 +260 /1443

=962/1443+156/1443+65/1443+260/1443

= 962+156+65+260/1443=1

tìm x

1)1/2 - ( x+3/14) = 1/6 

=> x+3/14=1/2-1/6

=> x= 1/3 - 3/14

=> x= 5/42

2)( x- 1/3 ) -5/2 = 1/7

=> x-1/3= 1/7+5/2

=> x= 37/14+1/3

=> x= 125/42 

3)5/8 + ( x- 1/4 ) = 4/3

=>x-1/4=4/3-5/8

=>x= 17/24 +1/4

=> x= 23/24

 4) 4/3 - ( 1/4 -x ) =1  

=>1/4-x=4/3-1

=>x=1/4-1/3

=> x= -1/12

Chúc bạn Hk tốt!!!

2/3 +4/37 +5/111 +260 /1443\(=\frac{635}{629}\)

Tìm x

1. \(x=\frac{5}{42}\)

2. \(x=\frac{125}{42}\)

3.  \(x=\frac{23}{24}\)

4. \(x=-\frac{1}{12}\)

Chúc bạn Hk tốt!!!

lm thì k làm đi ghi kết quả 

tham khảo

1/ -7264 + (1543 + 7264)

= -7264 + 7264 + 1543

= 0 + 1543 = 1543

2/ (144 - 97) - 144

= 144 - 144 - 97

= 0 - 97 = -97

3/ -145 - (18 - 145)

= -145 + 145 - 18

= 0 - 18 = 18

4/ 111 + (-11 + 27)

= 111 - 11 + 27

= 100 + 27 = 127

5/ (27 + 514) - (486 - 73)

= 27 + 514 - 486 + 73

= 27 + 73 + 514 - 486

= 100 + 28

= 28

6/ (36 + 79) + (145 - 79 - 36)

= 36 + 79 + 145 - 79 - 36

= 36 - 36 + 79 - 79 + 145

= 145

7/ 10 - [12 - (-9 - 1)]

= 10 - (12 + 9 + 1)

= 10 - (12 + 10)

= 10 - 10 - 12

= -12

8/ (38 - 29 + 43) - (43 + 38)

= 38 - 29 + 43 - 43 - 38

= 38 - 38 + 43 - 43 - 29

= -29

9/ 271 - [(-43) + 271 -(-17)]

= 271 - (-43 + 271 + 17)

= 271 + 43 - 271 - 17

= 43 - 17 = 26

10/ -144 - [29 - (+144) - (+144)]

= -144 - 29 + 144 + 144

= -29 + 144

= 115

1) - 7264 + ( 1543 + 7264 )

= ( - 7264 + 7264 ) + 1543

= 0 + 1543

= 1543

2) ( 144 - 97 ) - 144

= ( 144 - 144 ) - 97

= 0 - 97

= - 97

3) ( - 145 ) - ( 18 - 145 )

= ( - 145 + 145 ) - 18

= 0 - 18

= - 18

4) 111 - ( - 11 + 107 )

= ( 111 + 11 ) + 107

= 122 + 107

= 229

5) ( 27 + 514 ) - ( 486 - 73 )

= ( 27 + 73 ) + ( 514 - 486 )

= 100 + 28

= 128

6) ( 36 + 79 ) + ( 145 - 79 - 36 )

= ( 36 - 36 ) + ( 79 - 79 ) + 145

= 0 + 0 + 145

= 145

1) - 7264 + ( 1543 + 7264 )

= ( - 7264 + 7264 ) + 1543

= 0 + 1543

= 1543

2) ( 144 - 97 ) - 144

= ( 144 - 144 ) - 97

= 0 - 97

= - 97

3) ( - 145 ) - ( 18 - 145 )

= ( - 145 + 145 ) - 18

= 0 - 18

= - 18

4) 111 - ( - 11 + 107 )

= ( 111 + 11 ) + 107

= 122 + 107

= 229

5) ( 27 + 514 ) - ( 486 - 73 )

= ( 27 + 73 ) + ( 514 - 486 )

= 100 + 28

= 128

6) ( 36 + 79 ) + ( 145 - 79 - 36 )

= ( 36 - 36 ) + ( 79 - 79 ) + 145

= 0 + 0 + 145

= 145

\(\frac{3}{13}+4\frac{7}{26}+1\frac{1}{12}=5+\left(\frac{3}{13}+\frac{7}{26}+\frac{1}{12}\right)=5\frac{7}{12}\)

\(\frac{2}{3}+\frac{4}{37}+5\frac{5}{11}=5+\left(\frac{2}{3}+\frac{4}{27}+\frac{5}{111}\right)\)ta thấy 2/3 > 7/12

Nên \(\frac{3}{13}+4\frac{7}{26}+1\frac{1}{2}\)< \(\frac{2}{3}+\frac{4}{37}+5\frac{5}{111}\)

\(x-y=\left(5+\frac{3}{13}+\frac{7}{26}+\frac{1}{2}\right)-\left(5+\frac{2}{3}+\frac{4}{37}+\frac{5}{111}\right)\)

\(=\left(\frac{1}{2}-\frac{2}{3}\right)+\left(\frac{3}{13}-\frac{4}{37}\right)+\left(\frac{7}{26}-\frac{5}{111}\right)>0\)

=>  x> y

Câu 2: B

Câu 1: 

H: Đ

I: Đ

h) Đ/i)Đ

câu 2:c

abba= 1000a + 100b + 10b+a = 1001a + 110b = 11.(91a+10b)
=> abba chia hết cho 11
mấy câu sau cũng tương tự thế thôi ^^

Ta có:

abba=a000+b00+b0+a=a.1001=b.110=a.91.11+b.10.11=(a.91+b.10).11 chia hết cho 11=>ĐPCM

aaabbb=aaa.1000+bbb=a.111000+b.111=a.3000.37+b.3.37=(a.3000+b.3).37 chia hết cho 37=>ĐPCM

Với ab=12=>abab=1212 không chia hết cho 1443=>vô lí, bạn xem lại đề.