K
Khách

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

11 tháng 7 2023

\(\dfrac{-1}{21}+\dfrac{-1}{14}=\dfrac{-2}{42}+\dfrac{-3}{42}=\dfrac{-5}{42}\)

`@` `\text {Ans}`

`\downarrow`

`-1/21 + (-1/14)`

`= -1/21 - 1/14`

`= -2/42 - 3/42`

`= -5/42`

6 tháng 2 2016

1.-14*63+(-14)*37=-14*(63+37)=-14*100=-1400

2.-21*21+21*(-79)=21*[-21+(-79)]=21*(-100)=-2100

cho mình nha!Thank you!

6 tháng 2 2016

1. = - 14* ( 63 + 37) 

    = -14*100

    = -1400

2. = [ -21 + ( -79) ] *21

   = ( - 100) * 21

   = - 2100

a: =1/8-1/8+2/5=2/5

b: =(-1/15-14/15)+(23/27+31/27)=2-1=1

c: \(=\dfrac{3}{7}\left(\dfrac{22}{21}+\dfrac{5}{21}+\dfrac{15}{21}\right)=\dfrac{3}{7}\cdot2=\dfrac{6}{7}\)

d: \(=\dfrac{-8}{9}\cdot\dfrac{3}{2}+\dfrac{1}{9}\cdot\dfrac{-3}{2}=-\dfrac{3}{2}\)

a: 7/9-2/3=1/9

b: 1/3-(-2/15)=7/15

c: -11/14-(-4/2)=-3/14

d: a/21=5/21+2/3=5/21+14/21=19/21

hay a=19

27 tháng 3

a; \(\dfrac{9}{4}\) - \(\dfrac{-11}{4}\)

\(\dfrac{9}{4}\) + \(\dfrac{11}{4}\)

\(\dfrac{20}{4}\)

= 5 

b; \(\dfrac{7}{8}\) - \(\dfrac{3}{-8}\) - \(\dfrac{1}{8}\)

=  \(\dfrac{7}{8}\) + \(\dfrac{3}{8}\) - \(\dfrac{1}{8}\)

\(\dfrac{7+3-1}{8}\)

\(\dfrac{9}{8}\) 

27 tháng 3

c; \(\dfrac{-5}{21}\) - \(\dfrac{25}{21}\) - \(\dfrac{-1}{21}\)

  = \(\dfrac{-5}{21}\) - \(\dfrac{25}{21}\) + \(\dfrac{1}{21}\)

 =  \(\dfrac{-5-25+1}{21}\)

\(\dfrac{-29}{21}\)

23 tháng 8 2023

a) \(\dfrac{-15}{4}:\dfrac{21}{-10}=\dfrac{-15}{4}.\dfrac{-10}{21}=\dfrac{25}{14}\)

b) \(\dfrac{-7}{14}:\left(-0,14\right)=\dfrac{-7}{14}.\dfrac{-50}{7}=\dfrac{25}{7}\)

c) \(\left(\dfrac{-11}{15}\right):1\dfrac{1}{10}=\dfrac{-11}{15}.\dfrac{10}{11}=\dfrac{-2}{3}\)

d) \(2\dfrac{1}{7}:1\dfrac{1}{14}=\dfrac{15}{7}.\dfrac{14}{15}=2\)

23 tháng 8 2023

\(a.-\dfrac{15}{4}:\left(\dfrac{21}{-10}\right)\)

\(=-\dfrac{15}{4}\cdot\left(-\dfrac{10}{21}\right)\)

\(=\dfrac{25}{14}\)

\(b.-\dfrac{7}{14}:\left(-0,14\right)\)

\(=-\dfrac{1}{2}:\left(-\dfrac{7}{50}\right)\)

\(=\dfrac{25}{7}\)

\(c.\left(-\dfrac{11}{15}\right):\left(1\dfrac{1}{10}\right)\)

\(=\left(-\dfrac{11}{15}\right):\dfrac{11}{10}\)

\(=-\dfrac{2}{3}\)

\(d.\left(2\dfrac{1}{7}\right):\left(1\dfrac{1}{14}\right)\)

\(=\dfrac{15}{7}:\dfrac{15}{14}\)

\(=2\)

 

20 tháng 7 2023

1)1/6 - - 5/6 = 1/6 + 5/6 = 1

2)6/13 - -14/39 = 6/13 + 14/39= 32/39

3)4/5 - 4/-18 = 4/5 + 4/18= 46/45

4)7/21 - 9/-36 = 7/21 + 9/36 = 7/12

5)-12/18 - -21/35  = -12/18 + 21/35 = -1/15

6)-3/21 - 6/42 = -2/7

7)-18/24 - 15/21 = -41/28

8)1/6 - 2/5 =-7/30

24 tháng 4 2022

\(\dfrac{6}{21}-\dfrac{-12}{44}+\dfrac{10}{12}-\dfrac{-1}{4}-\dfrac{18}{33}\)

\(=\dfrac{6}{21}+\dfrac{12}{44}+\dfrac{10}{12}+\dfrac{1}{4}-\dfrac{18}{33}\)

\(=\dfrac{1013}{924}\)

24 tháng 4 2022

\(\dfrac{6}{21}-\dfrac{-12}{44}+\dfrac{10}{44}-\dfrac{1}{-4}-\dfrac{18}{33}\)

\(=\dfrac{2}{7}+\dfrac{3}{11}+\dfrac{5}{7}+\dfrac{1}{4}-\dfrac{9}{11}\)

\(=\left(\dfrac{2}{7}+\dfrac{5}{7}\right)+\left(\dfrac{3}{11}-\dfrac{9}{11}\right)+\dfrac{1}{4}\)

\(=1+-\dfrac{6}{11}+\dfrac{1}{4}\)

\(=\dfrac{5}{11}+\dfrac{1}{4}\)

\(=\dfrac{31}{44}\)