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1 tháng 7

(35 x 2 - 35:5 x 10) x (1 + 3 + 5 + ... + 19)

= [35 x 2 - 35 x (10 : 5) ] x (1 + 3 + 5 + ... + 19) 

= (35 x 2 - 35 x 2) x (1 + 3 + 5 +... + 19)

= (70 - 70) x (1 + 3 + 5 + .... + 19) 

= 0 x (1 + 3 + 5 + ... + 19)

= 0

1 tháng 7

   (35 x 2 - 35: 5 x 10) x (1 + 3 + 5 + ... + 17 + 19)

= (70 - 7 x 10) x (1 + 3 + 5 + ... + 17 + 19)

= (70 - 70) x (1 + 3 + 5 + ... + 17 + 19)

= 0 x (1 + 3 + 5 + ... +17 + 19)

= 0 

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

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

 =  \(\dfrac{-5-25+1}{21}\)

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

11 tháng 12 2016

1. a, (-17)+5+8+17+(-3)

=(-17+17)+(8+-3)+5

=0+5+5

=10

b, 25.2^2-(15-18)+12-19+10

=25.4-(-3)+12-19+10

=100+3+12-19+10

=(100+10)+(3+12)-19

=110+15-19

=125-19

=106

2, x+5=20-(12-7)

x+5=20-5=15

x=10

b,35-3lxl=5.(2^3-4)

35-3lxl=5.4=20

3lxl=15

lxl=5

vậy x=5 hoặc x=(-5)

11 tháng 12 2016

thank you

nhớ khi nào có câu hỏi lại trả lời hộ mình nhé

31 tháng 3 2021

mai mình thi rồi, các bạn giúp mình với

Câu 3:

a) \(\dfrac{12}{36}=\dfrac{12:12}{36:12}=\dfrac{1}{3}\)

\(\dfrac{-16}{20}=\dfrac{-16:4}{20:4}=\dfrac{-4}{5}\)

b) \(\dfrac{21}{105}=\dfrac{21:21}{105:21}=\dfrac{1}{5}\)

\(\dfrac{35}{150}=\dfrac{35:5}{150:5}=\dfrac{7}{30}\)

Câu 4: 

a) \(\dfrac{3}{10}+\dfrac{5}{10}=\dfrac{3+5}{10}=\dfrac{8}{10}=\dfrac{4}{5}\)

b) Ta có: \(\left(-27\right)\cdot36+64\cdot\left(-27\right)+23\cdot\left(-100\right)\)

\(=\left(-27\right)\cdot\left(64+36\right)+23\cdot\left(-100\right)\)

\(=-27\cdot100-23\cdot100\)

\(=100\left(-27-23\right)\)

\(=-50\cdot100=-5000\)

c) \(\dfrac{5}{8}+\dfrac{3}{12}=\dfrac{15}{24}+\dfrac{6}{24}=\dfrac{21}{24}=\dfrac{7}{8}\)

d) Ta có: \(\dfrac{-2}{17}+\dfrac{3}{19}+\dfrac{-15}{17}+\dfrac{16}{19}+\dfrac{5}{6}\)

\(=\left(-\dfrac{2}{17}+\dfrac{-15}{17}\right)+\left(\dfrac{3}{19}+\dfrac{16}{19}\right)+\dfrac{5}{6}\)

\(=-1+1+\dfrac{5}{6}\)

\(=\dfrac{5}{6}\)

27 tháng 7 2023

có đúng ko

 

11 tháng 9 2016

a) \(\frac{9}{22}\cdot\frac{33}{8}=\frac{3^2\cdot3\cdot11}{2\cdot11\cdot2^3}=\frac{3^4}{2^4}=\frac{81}{16}\)

b) \(\frac{12}{35}:\frac{36}{35}=\frac{2^2\cdot3}{2^2\cdot3^2}=\frac{1}{3}\)

c) \(\frac{19}{17}:\frac{76}{51}=\frac{19\cdot3\cdot17}{17\cdot2^2\cdot19}=\frac{3}{4}\)

`@` `\text {Ans}`

`\downarrow`

`a)`

\(\dfrac{1}{2}-\dfrac{5}{6}+\dfrac{11}{33}-\dfrac{35}{40}\)

`=`\(\dfrac{1}{2}-\dfrac{5}{6}+\dfrac{1}{3}-\dfrac{7}{8}\)

`=`\(\dfrac{12}{24}-\dfrac{20}{24}+\dfrac{8}{24}-\dfrac{21}{24}\)

`= -21/24 = -7/8`

`b)`

\(\dfrac{2}{3}\cdot1\dfrac{3}{4}-\dfrac{8}{9}-\dfrac{17}{51}-\dfrac{1}{5}\)

`=`\(\dfrac{2}{3}\cdot\dfrac{7}{4}-\dfrac{8}{9}-\dfrac{17}{51}-\dfrac{1}{5}\)

`=`\(\dfrac{7}{6}-\dfrac{8}{9}-\dfrac{17}{51}-\dfrac{1}{5}\)

`=`\(\dfrac{5}{18}-\dfrac{17}{51}-\dfrac{1}{5}\)

`=`\(-\dfrac{1}{18}-\dfrac{1}{5}=-\dfrac{23}{90}\)

`c)`

\(\dfrac{1}{2}\cdot2-2\dfrac{5}{7}+\dfrac{6}{4}-\dfrac{10}{15}\)

`=`\(1-\dfrac{19}{7}+\dfrac{6}{4}-\dfrac{10}{15}\)

`=`\(-\dfrac{12}{7}+\dfrac{6}{4}-\dfrac{10}{15}\)

`=`\(-\dfrac{3}{14}-\dfrac{10}{15}=-\dfrac{37}{42}\)

`d) `

\(\dfrac{1}{6}\cdot\dfrac{1}{11}+\dfrac{4}{11}\cdot\left(-\dfrac{1}{6}\right)+\dfrac{8}{11}\cdot\dfrac{1}{6}+\dfrac{1}{6}\cdot\dfrac{6}{11}\)

`=`\(\dfrac{1}{6}\cdot\left(\dfrac{1}{11}-\dfrac{4}{11}+\dfrac{8}{11}+\dfrac{6}{11}\right)\)

`=`\(\dfrac{1}{6}\cdot\left(\dfrac{1-4+8+6}{11}\right)\)

`=`\(\dfrac{1}{6}\cdot1=\dfrac{1}{6}\)

`e)`

\(-17\cdot\left(-23\right)+\left(-53\right)\cdot17+17\cdot14+17\cdot\left(-24\right)\)

`= 17*(23-53+14-24)`

`= 17*(-40)`

`= -680`

`f)`

\(-19\cdot218+\left(-82\right)\cdot19-533\cdot19+\left(-19\right)\cdot167\)

`= 19*(-218-82-533-167)`

`= 19*(-1000)`

`= -19000`

`g)`

\(\dfrac{2}{5}+\dfrac{3}{8}-\dfrac{11}{44}+\dfrac{9}{16}\)

`=`\(\dfrac{2}{5}+\dfrac{3}{8}-\dfrac{1}{4}+\dfrac{9}{16}\)

`=`\(\dfrac{31}{40}-\dfrac{1}{4}+\dfrac{9}{16}\)

`=`\(\dfrac{21}{40}+\dfrac{9}{16}=\dfrac{87}{80}\)

`h)`

\(\dfrac{4}{10}-1\dfrac{5}{6}\cdot2+\dfrac{7}{8}-\dfrac{1}{9}\)

`=`\(\dfrac{4}{10}-\dfrac{11}{6}\cdot2+\dfrac{7}{8}-\dfrac{1}{9}\)

`=`\(\dfrac{4}{10}-\dfrac{11}{3}+\dfrac{7}{8}-\dfrac{1}{9}\)

`=`\(-\dfrac{49}{15}+\dfrac{7}{8}-\dfrac{1}{9}\)

`=`\(-\dfrac{287}{120}-\dfrac{1}{9}=-\dfrac{901}{360}\)

`i )`

\(3\cdot\dfrac{1}{5}-\dfrac{2}{8}-\dfrac{12}{36}+\dfrac{15}{9}\)

`=`\(\dfrac{3}{5}-\dfrac{1}{4}-\dfrac{1}{3}+\dfrac{15}{9}\)

`=`\(\dfrac{7}{20}-\dfrac{1}{3}+\dfrac{15}{9}\)

`=`\(\dfrac{1}{60}+\dfrac{15}{9}=-\dfrac{33}{20}\)

`k)`

\(\dfrac{6}{8}\cdot3\dfrac{1}{2}+4\dfrac{2}{3}-\dfrac{11}{55}+\dfrac{17}{51}\)

`=`\(\dfrac{3}{4}\cdot\dfrac{7}{2}+\dfrac{14}{3}-\dfrac{1}{5}+\dfrac{17}{51}\)

`=`\(\dfrac{21}{8}+\dfrac{14}{3}-\dfrac{1}{5}+\dfrac{17}{51}\)

`=`\(\dfrac{175}{24}-\dfrac{1}{5}+\dfrac{17}{51}\)

`=`\(\dfrac{851}{120}+\dfrac{17}{51}=\dfrac{297}{40}\)

`l )`

\(\dfrac{1}{3}\cdot3\dfrac{1}{2}-4\dfrac{2}{5}-\dfrac{26}{78}+\dfrac{17}{51}\)

`=`\(\dfrac{1}{3}\cdot\dfrac{7}{2}-\dfrac{22}{5}-\dfrac{1}{3}+\dfrac{17}{51}\)

`=`\(\dfrac{1}{3}\left(\dfrac{7}{2}-1\right)-\dfrac{22}{5}+\dfrac{17}{51}\)

`=`\(\dfrac{1}{3}\cdot\dfrac{5}{2}-\dfrac{22}{5}+\dfrac{17}{51}\)

`=`\(\dfrac{5}{6}-\dfrac{22}{5}+\dfrac{17}{51}\)

`=`\(-\dfrac{107}{30}+\dfrac{17}{51}=-\dfrac{97}{30}\)

P/s: Bạn tách bài ra hỏi nhé! Và ghi đề rõ ràng chứ đừng ghi ntnay, nhiều bạn nhìn vào rất khó nhìn!

`# \text {KaizulvG}`

GH
26 tháng 6 2023

9 tháng 8 2015

a) = 17/19 - 17/19 + 27/35 + 35/35 = 0 + 62/35

b) = 1/3 x 4/5 + 1/3 x6/5 + 1/3 x 2 = 1/3(4/5 + 6/5 + 2) = 1/3 x 4 = = 4/3

c) 4/7 x 2/9 + 4/7 x 7/9 + 2/3 = 4/7 x (2/9 + 7/9) + 2/3 = 4/7 x 1 + 2/3 = 26/21

4 tháng 3 2022

A) 17/19 - 17/19 + 27/35 + 35/35 = 0 + 62/35

B) 1/3 x 4/5 + 1/3 x 6/5 + 1/3 x 2 = 1/3 x(4/5 + 6/5 x 2 ) = 1/3 x 4 = 4/3

c) TƯƠNG TỰ CÂU A VÀ B

* HOKTOT*

NHA

2 tháng 8 2015

bạn lên mạng tra từng câu 1 sẽ có

3 tháng 8 2015

ukm cảm ơn bạn nhìu