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\(4^0\cdot9^3-6^9\cdot\dfrac{120}{8^4\cdot3^{12}+6^{11}}\) hay \(4^0\cdot9^3-6^9\cdot\dfrac{120}{8^4}\cdot3^{12}+6^{11}\)?

26 tháng 4 2020

\(A=\frac{12}{40}+\frac{12}{88}+\frac{12}{154}+\frac{12}{238}+\frac{12}{340}\)

\(A=\frac{12}{5\times8}+\frac{12}{8\times11}+\frac{12}{11\times14}+\frac{12}{14\times17}+\frac{12}{17.20}\)

\(A=4\times\left(\frac{3}{5\times8}+\frac{3}{8\times11}+\frac{3}{11\times14}+\frac{3}{14\times17}+\frac{3}{17\times20}\right)\)

\(A=4\times\left(\frac{1}{5}-\frac{1}{8}+\frac{1}{8}-\frac{1}{11}+\frac{1}{11}-\frac{1}{14}+\frac{1}{14}-\frac{1}{17}+\frac{1}{17}-\frac{1}{20}\right)\)

\(A=4\times\left(\frac{1}{5}-\frac{1}{20}\right)\)

\(A=4\times\frac{3}{20}=\frac{12}{20}=\frac{3}{5}\)

21 tháng 1 2022

\(\dfrac{-5}{6}.\dfrac{4}{19}+\dfrac{-7}{12}.\dfrac{4}{19}-\dfrac{40}{57}.\)

\(=\dfrac{4}{19}.\left(\dfrac{-5}{6}+\dfrac{-7}{12}\right)-\dfrac{40}{57}.\)

\(=\dfrac{4}{19}.\dfrac{-17}{12}-\dfrac{40}{57}.\)

\(=\dfrac{-17}{57}-\dfrac{40}{57}=-1.\)

b: \(B=\dfrac{5}{2}-\dfrac{7}{2}+\dfrac{3}{8}+\dfrac{6}{8}+\dfrac{-6}{11}-\dfrac{5}{11}=-2-1+\dfrac{9}{8}=\dfrac{9}{8}-3=-\dfrac{15}{8}\)

c: \(C=\left(\dfrac{4}{3}+\dfrac{7}{3}+\dfrac{1}{3}\right)+\left(\dfrac{2}{5}+\dfrac{3}{5}\right)=4+1=5\)

d: \(D=\dfrac{4}{19}\left(\dfrac{-5}{6}-\dfrac{7}{12}\right)-\dfrac{40}{57}\)

\(=\dfrac{4}{19}\cdot\dfrac{-17}{12}-\dfrac{40}{57}=-1\)

e: \(E=\dfrac{1}{3}\left(\dfrac{4}{5}-\dfrac{9}{5}\right)+\dfrac{2}{3}=\dfrac{2}{3}-\dfrac{1}{3}=\dfrac{1}{3}\)

23 tháng 7 2015

= 33

= 69

= 69

= 91

= 59

= 69

= 98

= 70

= 95

= 100

 

25 tháng 7 2015

21+12=33

56+13=69

59+10=69

50+41=91

19+40=59

57+12=69

90+8=98

50+20=70

72+23=95

50+50=100

27 tháng 7 2023

45-58+(-45)+(+58)-3=45-58-45+58-3=(45-45)+(58-58)-3=-3

(-57)-(-12)+3-(-57)=-57+12+3+57=(-57+57)+12+3=15

-(-24)-(-30)+(-24)-30+8=24+30-24-30+8=(24-24)+(30-30)+8=8

-(-12)+(+19)-(+12)+8-19=12+19-12+8-19=(12-12)+(19-19)+8=8

47-(-53)+(-47)-(+53)=47+53-47-53=(47-47)+(53-53)=0

-(+28)+32-(-28)+(-34)=-28+32+28-34=(-28+28)-(34-32)=-2

15-(+72)+(-15)+(+72)=15-72-15+72=(15-15)+(72-72)=0

20-(+46)+(-25)-(-46)=20-46-25+46=(20-25)+(46-46)=-5

28-(-32)+(-28)-32+5=28+32-28-32+5=(28-28)+(32-32)+5=5

-75+(-49)+(+75)+49-12=-75-49+75+49-12=(-75+75)+(49-49)-12=-12

 

 

27 tháng 7 2023

\(...=45-58-45+58-3=-3\)

\(...=-57+12+3+57=15\)

\(...=24+30-24-30+8=8\)

\(...=12+19-12+8-19=8\)

\(...=47+53-47-53=0\)

\(...=-28+32+28-34=-2\)

\(...=15-72-15+72=0\)

\(...=20-46-25+46=-5\)

\(=...28+32-28-32+5=5\)

\(...=-75-49+75+49-12=-12\)

7 tháng 7 2021

Ta có \(\dfrac{x}{19}=\dfrac{3xx}{19x3}=\dfrac{3x}{57x}\)

Lại có: \(\dfrac{x}{19}< \dfrac{12}{57}\)\(\Leftrightarrow\dfrac{3x}{57}< \dfrac{12}{57}\)\(\Leftrightarrow3x< 12\Leftrightarrow x=\left\{0;1;2;3\right\}\)

P/s Nhớ tick cho mình nha. Thanks bạn

 

15 tháng 4 2019

\(\left(19\frac{5}{8}:\frac{7}{12}-13\frac{1}{4}:\frac{7}{12}\right).\frac{4}{5}\)

\(=\left(\frac{157}{8}:\frac{7}{12}-\frac{53}{4}:\frac{7}{12}\right).\frac{4}{5}\)

\(=\left[\left(\frac{157}{8}-\frac{53}{4}\right):\frac{7}{12}\right].\frac{4}{5}\)

\(=\left[\frac{51}{8}:\frac{7}{12}\right].\frac{4}{5}\)

\(=\frac{153}{14}.\frac{4}{5}\)

\(=\frac{306}{35}\)

15 tháng 4 2019

\(\left(\frac{-2}{5}+\frac{3}{7}\right)-\left(\frac{4}{9}+\frac{12}{20}-\frac{13}{35}\right)+\frac{7}{35}\)

\(=\frac{1}{35}-\frac{212}{315}+\frac{7}{35}\)

\(=\frac{1}{35}+\frac{-212}{315}+\frac{7}{35}\)

\(=\frac{9}{315}+\frac{-212}{315}+\frac{63}{315}\)

\(=\frac{-140}{315}=\frac{-4}{9}\)