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11 tháng 4

\(1\dfrac{13}{15}\cdot0,75-\left(\dfrac{8}{15}+25\%\right)\)

\(=\dfrac{28}{15}\cdot\dfrac{3}{4}-\left(\dfrac{8}{15}+\dfrac{1}{4}\right)\)

\(=\dfrac{7}{5}-\dfrac{8}{15}-\dfrac{1}{4}\)

\(=\dfrac{21}{15}-\dfrac{8}{15}-\dfrac{1}{4}\)

\(=\dfrac{13}{15}-\dfrac{1}{4}\)

\(=\dfrac{37}{60}\)

1 tháng 6 2020

Câu hỏi bạn viết hơi khó hiểu. Dịch ra thành 2 trường hợp

TH1: 113/15×0,75-(8/15+25%)=73/15

TH2:13/15×0,75-(8/15+25%)=-2/1

K MK NHA

113/15.3/4-(8/15+1/4)

113/15.3/4-(32/60+15/60)

113/15.3/4-47/60

339/60-47/60

292/60

27 tháng 3 2017

\(=\frac{113}{15}.0,75-\left(\frac{11}{20}+25\%\right):\frac{7}{5}\)

\(=5,65-\left(\frac{11}{20}+25\%\right):\frac{7}{5}\)

\(=5,65-\frac{4}{5}:\frac{7}{5}\)

\(=5,65-\frac{4}{7}\)

\(=\frac{711}{140}\)

11 tháng 4 2019

1. 

a)

3/4- 3/2+1/2 . 12/5

=-3/4+6/5

=9/20

b)

8 . x-7,8 . x=25

0,2 x= 25

x=25 : 0,2

x=125

c)1/4 . 4/3 . 30. 1/2. 8/45

=8/9

đ)  9/2+ 3/4 x =27/8

              3/4x= -9/8

       x=-9/8 : 3/4

  x=-3/2

 b2:

a) 13/15 . 3/4-(8/15+1/4)

    =39/60  - 47/60

 = -8/60 = -2/15

2 tháng 8 2015

\(1\frac{13}{15}.0,75-\left(\frac{104}{195}+25\%\right).\frac{24}{47}-3\frac{12}{13}:3\)

\(=\frac{28}{15}.\frac{3}{4}-\left(\frac{8}{15}+\frac{1}{4}\right).\frac{8}{9}-\frac{51}{13}.\frac{1}{3}\)

\(=\frac{7}{5}-\left(\frac{32}{60}+\frac{15}{60}\right).\frac{8}{9}-\frac{17}{13}\)

\(=\frac{7}{5}-\frac{47}{60}.\frac{8}{9}-\frac{17}{13}\)

\(=\frac{7}{5}-\frac{94}{135}-\frac{17}{13}\)

\(=\frac{-212}{351}\)

Tự quy đồng

 

\(2\frac{3}{4}.\left(-0,4\right)-1\frac{3}{5}.2,75+\left(-1,2\right):\frac{4}{11}\)

\(=\frac{11}{4}.\frac{-2}{5}-\frac{8}{5}.\frac{11}{4}-\frac{6}{5}.\frac{11}{4}\)

\(=\frac{11}{4}.\left(\frac{-2}{5}-\frac{8}{5}-\frac{6}{5}\right)\)

\(=\frac{11}{4}.\frac{-16}{5}\)

\(=\frac{-44}{5}=-8\frac{4}{5}\)

 

21 tháng 8 2020

a) \(\left(\frac{7}{8}-\frac{3}{4}\right)\cdot\frac{1}{3}-\frac{2}{7}\cdot\left(3,5\right)=\left(\frac{7}{8}-\frac{3}{4}\right)\cdot\frac{1}{3}-\frac{2}{7}\cdot\frac{7}{2}\)

\(=\left(\frac{7}{8}-\frac{6}{8}\right)\cdot\frac{1}{3}-1=\frac{1}{8}\cdot\frac{1}{3}-1=\frac{1}{24}-\frac{24}{24}=-\frac{23}{24}\)

b) \(\left(\frac{3}{5}+0,415-\frac{3}{200}\right)\cdot2\frac{2}{3}\cdot0,25\)

\(=\left(\frac{3}{5}+\frac{83}{200}-\frac{3}{200}\right)\cdot\frac{8}{3}\cdot\frac{1}{4}\)

\(=\left(\frac{3}{5}+\frac{80}{200}\right)\cdot\frac{8}{3}\cdot\frac{1}{4}=\left(\frac{3}{5}+\frac{2}{5}\right)\cdot\frac{8}{3}\cdot\frac{1}{4}=1\cdot\frac{8}{3}\cdot\frac{1}{4}=1\cdot\frac{2}{3}\cdot\frac{1}{1}=\frac{2}{3}\)

c) \(\frac{5}{16}:0,125-\left(2\frac{1}{4}-0,6\right)\cdot\frac{10}{11}\)

\(=\frac{5}{16}:\frac{1}{8}-\left(\frac{9}{4}-\frac{3}{5}\right)\cdot\frac{10}{11}\)

\(=\frac{5}{16}\cdot8-\frac{33}{20}\cdot\frac{10}{11}=\frac{5}{2}-\frac{3}{2}=1\)

d) \(0,25:\left(10,3-9,8\right)-\frac{3}{4}=\frac{1}{4}:\left(\frac{103}{10}-\frac{98}{10}\right)-\frac{3}{4}\)

\(=\frac{1}{4}:\frac{1}{2}-\frac{3}{4}=\frac{1}{4}\cdot2-\frac{3}{4}=\frac{2}{4}-\frac{3}{4}=-\frac{1}{4}\)

Câu cuối tương tự

a: \(=\dfrac{5}{6}\cdot\dfrac{-12}{7}=\dfrac{-10}{7}\)

b: \(=\dfrac{7}{8}\cdot\dfrac{8}{14}=\dfrac{7}{14}=\dfrac{1}{2}\)

c: \(=\dfrac{4}{5}\cdot\dfrac{-15}{8}=\dfrac{-3}{2}\)

d: \(=\dfrac{15}{16}\cdot\dfrac{8}{25}=\dfrac{15}{25}\cdot\dfrac{1}{2}=\dfrac{3}{5}\cdot\dfrac{1}{2}=\dfrac{3}{10}\)

đ: \(=\dfrac{2}{3}-\dfrac{70}{175}=\dfrac{2}{3}-\dfrac{2}{5}=\dfrac{10-6}{15}=\dfrac{4}{15}\)

`@` `\text {Ans}`

`\downarrow`

`1,`

`a)`

`-7/25 + (-8)/25`

`= (-7 - 8)/25`

`= -15/25`

`= -3/5`

`b)`

`6/13 + (-15)/39`

`= 18/39 + (-15)/39`

`= (18 - 15)/39`

`= 3/39`

`= 1/13`

`c)`

`5/7 + 4/(-14)`

`= 10/14 + (-4)/14`

`= (10 - 4)/14`

`= 6/14`

`= 3/7`

`d)`

`-8/18 + (-15)/27`

`= -4/9 + (-5)/9`

`= (-4-5)/9`

`= -9/9 = -1`

20 tháng 7 2023

`2,`

`a)`

`3/5 + (-7)/4`

`= 12/20 + (-35)/20`

`= (12 - 35)/20`

`=-23/20`

`b)`

`(-2) + (-5)/8`

`= (-16)/8 + (-5)/8`

`= (-16 - 5)/8`

`= -21/8`

`c)`

`1/8 + (-5)/9`

`= 9/72 + (-40)/72`

`= (9-40)/72`

`= -31/72`

`d)`

`6/13 + (-14)/39`

`= 18/39 + (-14)/39`

`= (18 - 14)/39`

`= 4/39`

`e)`

`(-18)/24 + 15/21`

`= (-3)/4 + 5/7`

`= (-21)/28 + 20/28`

`= (-21 + 20)/28`

`= -1/28`

13 tháng 8 2023

a) \(\dfrac{-5}{9}-\dfrac{4}{15}+\dfrac{2}{9}-\dfrac{11}{15}\)

\(=\left(\dfrac{-5}{9}+\dfrac{2}{9}\right)-\left(\dfrac{4}{15}+\dfrac{11}{15}\right)\)

\(=\dfrac{-3}{9}-\dfrac{15}{15}\)

\(=-\dfrac{1}{3}-1\)

\(=-\dfrac{4}{3}\)

b) \(\dfrac{-8}{13}-\dfrac{7}{16}+\dfrac{21}{13}-\dfrac{1}{6}\)

\(=\left(\dfrac{-8}{13}+\dfrac{21}{13}\right)-\dfrac{7}{16}-\dfrac{1}{6}\)

\(=\dfrac{13}{13}-\dfrac{29}{48}\)

\(=1-\dfrac{29}{48}\)

\(=\dfrac{19}{48}\)

c) \(\dfrac{-15}{25}-\dfrac{14}{21}+\dfrac{8}{5}-\dfrac{5}{3}\)

\(=\dfrac{-3}{5}-\dfrac{2}{3}+\dfrac{8}{5}-\dfrac{5}{3}\)

\(=\left(\dfrac{-3}{5}+\dfrac{8}{5}\right)-\left(\dfrac{2}{3}+\dfrac{5}{3}\right)\)

\(=\dfrac{5}{5}-\dfrac{7}{3}\)

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

\(=-\dfrac{4}{3}\)

a: =-5/9+2/9-11/15-4/15

=-3/9-1

=-12/9=-4/3

b: =-8/13+21/13-7/16-1/6

=1-1/6-7/16

=5/6-7/16

=19/48

c: =-15/25+8/5-2/3-5/3

=-7/3+1

=-4/3

1) Ta có: \(\left(\dfrac{3}{4}\cdot\dfrac{5}{97}+\dfrac{1}{9}\cdot\dfrac{13}{47}\right)\cdot\left(\dfrac{1}{5}-\dfrac{7}{25}\cdot\dfrac{5}{7}\right)\)

\(=\left(\dfrac{3}{4}\cdot\dfrac{5}{97}+\dfrac{1}{9}\cdot\dfrac{13}{47}\right)\cdot\left(\dfrac{1}{5}-\dfrac{1}{5}\right)\)

=0

2) Ta có: \(\dfrac{8}{17}\cdot\dfrac{4}{15}+\dfrac{8}{17}\cdot\dfrac{22}{15}-\dfrac{8}{15}\cdot\dfrac{9}{17}\)

\(=\dfrac{8}{17}\left(\dfrac{4}{15}+\dfrac{22}{15}-\dfrac{9}{15}\right)\)

\(=\dfrac{8}{17}\cdot\dfrac{15}{15}=\dfrac{8}{17}\)

3) Ta có: \(\dfrac{2021}{2}\cdot\dfrac{1}{3}+\dfrac{4042}{4}\cdot\dfrac{1}{5}+\dfrac{6063}{3}\cdot\dfrac{22}{15}\)

\(=\dfrac{2021}{2}\left(\dfrac{1}{3}+\dfrac{1}{5}\right)+2021\cdot\dfrac{22}{15}\)

\(=\dfrac{2021}{2}\cdot\dfrac{8}{15}+\dfrac{2021}{2}\cdot\dfrac{44}{15}\)

\(=\dfrac{2021}{2}\cdot\dfrac{52}{15}\)

\(=\dfrac{52546}{15}\)

4) Ta có: \(\dfrac{4}{7}\cdot\dfrac{2}{13}+\dfrac{8}{13}:\dfrac{7}{4}+\dfrac{4}{7}:\dfrac{13}{2}+\dfrac{4}{7}\cdot\dfrac{1}{13}\)

\(=\dfrac{4}{7}\left(\dfrac{2}{13}+\dfrac{8}{13}+\dfrac{2}{13}+\dfrac{1}{13}\right)\)

\(=\dfrac{4}{7}\)

2 tháng 7 2021

cảm ơn nhé

vui