K
Khách

Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.

2 tháng 5 2018

                                                                         Bài làm

1.

11 3/13 - ( 2 4/7 + 5 3/13 )

= 11 3/13 - 2 4/7 - 5 3/13

= ( 11 3/13 - 5 3/13 ) - 2 4/7

= { (11 - 5 ) . ( 3/13 - 3/13 ) } - 2 4/7

= ( 6 . 0 ) - 2 4/7

= 0 - 2 4/7

= 2 4/7

= 18/7

2 .

19 5/8 : 7/12 + ( -15 1/4) : 7/12

= { 19 5/8 + ( -15 1/4 ) } : 7/12

= [ { 19 + ( - 15) } . ( 5/8 + 1/4 ) ] : 7/12

= { 4 . ( 5/8 + 2/8 ) } : 7/12

= ( 4 . 7/8 ) : 7/12

= 1.7/2 : 7/12

= 7/2 : 7/12

= 7/2 . 12/7

= 1.1/6.1

= 1/6

3 .

2/5 . 1/3 - 2 2/15 : 1/5 + 3/5 . 1/3

= 1/3 . ( 2/5 + 3/5 ) - 2 2/15 : 1/5

= 1/3 . 5/5 - 32/15 . 5/1

= 1/3 . 1 - 32.1/3.1

= 1/3 - 32/3

= -31/3

4 .

( 3 1/3 + 2,5 ) : ( 3 1/6 - 4 1/5 ) - 11/31

= ( 10/3 + 25/10 ) : { ( 3 - 4 ) . ( 1/6 - 1/5 ) - 11/31

= ( 10/3 + 5/2 ) : { (-1) . ( 5/30 - 6/30 ) } - 11/31

= ( 20/6 + 15/6 ) : { (-1) . (-1)/30 } - 11/31

= 35/6 : 1/30 - 11/31

= 35/6 . 30/1 - 11/31

= 35.5/1.1 - 11/31

= 175 - 11/31

= 5425/31 - 11/31

= 5414/31

5.

75% - 1 1/5 + 0,5 : 5/12 - (-1/2)2

= 75/100 - 6/5 + 5/12 - 1/4

= 3/4 - 6/5 + 5/12 - 1/4

= ( 3/4 - 1/4 ) + ( 5/12 - 6/5 )

= 2/4 + ( 25/60 - 30/60 )

= 1/2 + (-5)/60

= 1/2 + (-1)/12

= 6/12 + (-1)/12

= 5/12

Đúng thì k cho mình nha !

2 tháng 5 2018

1)

11 3/13 - ( 2 4/7 + 5 3/13 )

= 11 3/13 - 2 4/7 - 5 3/13

= ( 11 3/13 - 5 3/13 ) - 2 4/7

= { (11 - 5 ) . ( 3/13 - 3/13 ) } - 2 4/7

= ( 6 . 0 ) - 2 4/7

= 0 - 2 4/7

= 2 4/7

= 18/7

2 )

19 5/8 : 7/12 + ( -15 1/4) : 7/12

= { 19 5/8 + ( -15 1/4 ) } : 7/12

= [ { 19 + ( - 15) } . ( 5/8 + 1/4 ) ] : 7/12

= { 4 . ( 5/8 + 2/8 ) } : 7/12

= ( 4 . 7/8 ) : 7/12

= 1.7/2 : 7/12

= 7/2 : 7/12

= 7/2 . 12/7

= 1.1/6.1

= 1/6

3 )

2/5 . 1/3 - 2 2/15 : 1/5 + 3/5 . 1/3

= 1/3 . ( 2/5 + 3/5 ) - 2 2/15 : 1/5

= 1/3 . 5/5 - 32/15 . 5/1

= 1/3 . 1 - 32.1/3.1

= 1/3 - 32/3

= -31/3

4 )

( 3 1/3 + 2,5 ) : ( 3 1/6 - 4 1/5 ) - 11/31

= ( 10/3 + 25/10 ) : { ( 3 - 4 ) . ( 1/6 - 1/5 ) - 11/31

= ( 10/3 + 5/2 ) : { (-1) . ( 5/30 - 6/30 ) } - 11/31

= ( 20/6 + 15/6 ) : { (-1) . (-1)/30 } - 11/31

= 35/6 : 1/30 - 11/31

= 35/6 . 30/1 - 11/31

= 35.5/1.1 - 11/31

= 175 - 11/31

= 5425/31 - 11/31

= 5414/31

5)

75% - 1 1/5 + 0,5 : 5/12 - (-1/2)2

= 75/100 - 6/5 + 5/12 - 1/4

= 3/4 - 6/5 + 5/12 - 1/4

= ( 3/4 - 1/4 ) + ( 5/12 - 6/5 )

= 2/4 + ( 25/60 - 30/60 )

= 1/2 + (-5)/60

= 1/2 + (-1)/12

= 6/12 + (-1)/12

= 5/12

4 tháng 5 2018

1 .

[ 6 + ( 1/2 ) 3 - /-0,5/ ] : 3/12

= [ 6 + 1/8 - ( -5/10 ) ] . 12/3

= [ 6 + 1/8 + 5/10 ] .4

= [ 6 + 1/8 + 1/2 ] .4

= [ 48/8 + 1/8 + 4/8 ] .4

= 53/8 . 4

= 53 . 1/2

= 53/2

2.

1/3 + 5/4 : (-35/16)

= 1/3 + 5/4 . ( 16/-35 )

= 1/3 + 1 . 4/4 . (-7 )

= 1/3 + 4/28

= 1/3 + 1/7

= 7/21 + 3/21

= 10/21

3 .

11 3/13 - ( 2 4/7 + 5 3/13 )

= 11 3/13 - 2 4/7 - 5 3/13

= { [ ( 11 - 5 ) . ( 3/13 - 3/13 ) } - 2 4/7

= ( 6 . 0 ) - 2 4/7

= 0 - 18/7

= 18/7

4 .

1 3/7 + (-1/3 + 2 4/7 )

= 1 3/7 + ( -1 )/3 + 2 4/7

={ [ ( 1 + 2 ) . ( 3/7 + 4/7 ) } + ( -1 )/3

= ( 3 . 1 ) + ( -1 )/3

= 3 + ( -1 )/3

= 9/3 + ( -1 )/3

= 8/3

5 .

( 6 4/9 + 3 7/11 ) - 4 4/9

= 6 4/9 + 3 7/11 - 4 4/9

= { ( 6 - 4 ) . ( 4/9 - 4/9 ) } + 3 7/11

= ( 2 . 0 ) + 3 7/11

= 0 + 40/11

= 40/11

Nếu đúng thì k cho mình nha !

2 tháng 4 2016

nhiều giữ vậy bạn

19 tháng 6 2016

Bài 1:

a)12,5 x (-5/7) + 1,5 x (-5/7)

=-5/7*(12,5+1,5)

=-5/7*14

=-10

b)(-1/4) x (6|2/11) + 3|9/11 x (-1/4)

=-1/4*(68/11+42/11)

=-1/4*10

=-5/2

c tương tự

d)\(\frac{9^8\cdot4^3}{27^4\cdot6^5}=\frac{\left(3^2\right)^8\cdot\left(2^2\right)^3}{\left(3^3\right)^4\cdot\left(2\cdot3\right)^5}=\frac{3^{16}\cdot2^6}{3^{12}\cdot2^5\cdot3^5}=\frac{3^{16}\cdot2^5\cdot2}{3^{16}\cdot3^1\cdot2^5}=\frac{2}{3}\)

Bài 2:

a)Ta có:

2800=(28)100=256100

8200=(82)100=64100

Vì 256100>64100 =>2800>8200

b)Ta có:

1245=(123)15=172815

Vì 62515<172815 =>62515<1245

19 tháng 6 2016

a) -5/7x(12,5+1,5)=-10

b) -1/4x (6I2/11+3I9/11) = -1/4x 10=-5/2

c) (-7/5 + -3/8 + -3/5+5/8): 2009/2010 = -7/4:2009/2010=-1005/574

d)3^16x 4^3/3^12x 6^5=3^4x4^3x6^5=......

bài 2)

2^800=2^4x200= 15^200> 8^200

=> 2^800>8^200

B) quên cách làm

19 tháng 6 2016

a,12,5x(-5/7)+1,5x(-5/7)

=-125/14+-15/14

=-10

2,2mu800>8 mu 200

6254 lon hon 12

1 tháng 6 2019

\(A=\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+...+\frac{1}{2019.2020}\)

\(A=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{2019}-\frac{1}{2020}\)

\(A=1-\frac{1}{2020}\)

\(A=\frac{2019}{2020}\)

1 tháng 6 2019

\(B=\frac{1}{1.3}+\frac{1}{3.5}+\frac{1}{5.7}+...+\frac{1}{2017.2019}\)

\(2B=\frac{2}{1.3}+\frac{2}{3.5}=\frac{2}{5.7}+...+\frac{2}{2017.2019}\)

\(2B=1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}=\frac{1}{5}-\frac{1}{7}+...+\frac{1}{2017}-\frac{1}{2019}\)

\(2B=1-\frac{1}{2019}\)

\(2B=\frac{2018}{2019}\)

\(B=\frac{2018}{2019}:2=\frac{1009}{2019}\)