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6 tháng 3 2017

\(B=-\frac{2}{17}+\frac{15}{23}+-\frac{15}{17}+\frac{4}{19}+\frac{8}{23}\)

\(B=\left(-\frac{2}{17}+-\frac{15}{17}\right)+\left(\frac{15}{23}+\frac{8}{23}\right)+\frac{4}{19}\)

\(B=\left(-1\right)+1+\frac{4}{19}\)

\(B=0+\frac{4}{9}=\frac{4}{9}\)

\(C=-\frac{1}{2}+\frac{3}{21}+-\frac{2}{6}+-\frac{5}{30}\)

\(C=-\frac{1}{2}+\frac{1}{7}+-\frac{1}{3}+-\frac{1}{6}\)

\(C=\left(-\frac{1}{2}+-\frac{1}{3}+-\frac{1}{6}\right)+\frac{1}{7}\)

\(C=\left(-1\right)+\frac{1}{7}\)

\(C=-\frac{6}{7}\)

Ủng hộ tk Đúng nhé ! ^^ 

6 tháng 3 2017

 B= -2   +  15 + (-15) + 4 + 8

     17       23      17     19   23

B= [(-2)  +  (-15)] + [15 + 8]  + 4

     17        17         23    23    19

B= -1 +1+  4                vậy B=4

               19                          19

31 tháng 3 2017

\(A=8\frac{4}{17}-\left(2\frac{5}{9}+3\frac{4}{17}\right)\)

\(A=8\frac{4}{17}-2\frac{5}{9}-3\frac{4}{17}\)

\(A=\left(8\frac{4}{17}-3\frac{4}{17}\right)-\frac{23}{9}\)

\(A=5-\frac{23}{9}\)

\(A=\frac{45}{9}-\frac{23}{9}\)

\(A=\frac{22}{9}\)

31 tháng 3 2017

\(A=8\frac{4}{7}-2\frac{5}{9}-3\frac{4}{7}\)

\(A=\left(8\frac{4}{7}-3\frac{4}{7}\right)-2\frac{5}{9}\)

\(A=5-2\frac{5}{9}\)

\(A=4+1-2\frac{5}{9}\)

\(A=4+1-\frac{23}{9}\)

\(A=4+\frac{-14}{9}\)

\(A=1\frac{5}{9}\)

7 tháng 3 2017

A = 18:26+(-5):27+(-22):86+12:39+(-32):43 = 9:13+(-5):27+(-11):43+4:13+(-32):43 = (9:13+4:13)+[(-11):43+(-32):43]+(-5):27 = 1+(-1)+5:27 = -5:27

B =(-10):12+8:15+(-19):56+3:(-18)+28:60 = (-5):6+8:15+(-19):56+1:(-6)+7:15 = [(-5):6+1:(-6)]+(8:15+7:15)+(-19):56 = (-1)+1+(-19):56 = (-19) :56

1 tháng 8 2018

a, \(\frac{3}{8}+\frac{11}{13}-\frac{9}{13}\)

  =\(\frac{3}{8}+\frac{2}{13}\)

  =\(\frac{55}{104}.\)

b, \(\frac{2}{7}.\left(\frac{5}{9}+\frac{4}{9}\right)+\frac{2}{7}\)

  =\(\frac{2}{7}.\frac{9}{9}+\frac{2}{7}\)

  =\(\frac{2}{7}+\frac{2}{7}\)

  =\(\frac{4}{7}\)

c, \(\frac{3}{11}.\left(\frac{3}{5}-\frac{5}{3}\right)-\frac{3}{10}.\left(\frac{1}{3}-\frac{2}{5}\right)\)

  =\(\frac{3}{11}.-\frac{16}{15}-\frac{3}{10}.-\frac{1}{15}\)

  =\(-\frac{16}{55}--\frac{1}{50}\)

  =\(-\frac{149}{550}.\)

d, \(\frac{-3}{4}.\frac{11}{23}+\frac{3}{23}.\frac{31}{17}-\frac{3}{17}.\frac{19}{23}\)

  =\(-\frac{33}{92}+\frac{93}{391}-\frac{57}{391}\)

  =\(-\frac{417}{1564}\)

e, \(\frac{3}{17}.\frac{11}{23}+\frac{3}{23}.\frac{31}{17}-\frac{3}{17}.\frac{19}{23}\)

  =\(\frac{33}{391}+\frac{93}{391}--\frac{254}{391}\)

  =\(\frac{380}{391}.\)

g, \(\frac{3}{7}.\frac{-5}{12}+\frac{11}{17}:\frac{5}{-12}\)

  =\(-\frac{5}{28}+-\frac{132}{85}\)

  = \(-1.731512605.\)

k cho mình nha làm mỏi tay quá ,.....................kết bạn với mình nha.......................

5 tháng 8 2018

THANK  Ngô Bùi Hoa  làm cho mình bài 2 với 

15 tháng 8 2019

\(A=49\frac{8}{23}-\left(5\frac{7}{32}+14\frac{8}{23}\right)\)

\(A=49\frac{8}{23}-5\frac{7}{32}+14\frac{8}{23}\)

\(A= \left(49\frac{8}{23}-14\frac{8}{23}\right)-5\frac{7}{32}\)

\(A=\left[\left(49-14\right)-\left(\frac{8}{23}-\frac{8}{23}\right)\right]-5\frac{7}{32}\)

\(A=\left[35-0\right]-5\frac{7}{32}\)

\(A=35-5\frac{7}{32}\)

\(A=\frac{953}{32}\)

\(B=71\frac{38}{45}-\left(43\frac{38}{45}-1\frac{17}{57}\right)\)

\(B=71\frac{38}{45}-\frac{36377}{855}\)

\(B=\frac{1670}{57}\)

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

\(C=\left[\left(19\frac{5}{8}-13\frac{1}{4}\right):\frac{7}{12}\right]:\frac{4}{5}\)

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

\(C=\frac{153}{14}:\frac{4}{5}\)

\(C=\frac{765}{56}\)

\(D=\left[\left(\frac{10}{15}-\frac{2}{3}\right):\frac{1}{7}\right]\cdot0,15-\frac{1}{4}\)

\(D=\left[0:\frac{1}{7}\right]\cdot\frac{3}{20}-\frac{1}{4}\)

\(D=0\cdot\frac{3}{20}-\frac{1}{4}\)

\(D=0-\frac{1}{4}\)

\(D=-\frac{1}{4}\)

\(E=\frac{13}{30}+\frac{28}{45}\cdot2\frac{1}{2}-\left[\left(\frac{1}{2}+\frac{1}{3}\right):\frac{53}{90}\right]:\frac{50}{53}\)

\(E=\frac{13}{30}+\frac{28}{45}\cdot\frac{5}{2}-\left[\frac{5}{6}:\frac{53}{90}\right]:\frac{50}{53}\)

\(E=\frac{13}{30}+\frac{28}{45}\cdot\frac{5}{2}-\frac{75}{53}:\frac{50}{53}\)

\(E=\frac{13}{30}+\frac{14}{9}-\frac{3}{2}\)

\(\)\(E=\frac{22}{45}\)

CHUC BAN HOC TOT >.<

18 tháng 4 2018

\(A=\frac{\left(23\frac{11}{15}-26\frac{13}{20}\right)}{12^2+5^2}\cdot\frac{1-\frac{1}{30}-\frac{1}{42}-\frac{1}{56}}{3^2.13.2-13.5}-\frac{19}{37}\)

\(A=\frac{\left(23+\frac{11}{15}-26+\frac{13}{20}\right)}{144+25}\cdot\frac{1-\frac{1}{5.6}-\frac{1}{6.7}-\frac{1}{7.8}}{9.13.2-13.5}-\frac{19}{37}\)

\(A=\frac{\left(23+26+\frac{11}{15}-\frac{13}{20}\right)}{169}\cdot\frac{1-\left(\frac{1}{5}-\frac{1}{6}\right)-\left(\frac{1}{6}-\frac{1}{7}\right)-\left(\frac{1}{7}-\frac{1}{8}\right)}{13.\left(9.2-5\right)}-\frac{19}{37}\)

\(A=\frac{49+\frac{44}{60}-\frac{39}{60}}{169}\cdot\frac{1-\frac{1}{5}+\frac{1}{6}-\frac{1}{6}+\frac{1}{7}-\frac{1}{7}+\frac{1}{8}}{13.13}-\frac{19}{37}\)

\(A=\frac{49+\frac{1}{20}}{169}\cdot\frac{1-\frac{1}{5}+\frac{1}{8}}{169}-\frac{19}{37}\)

\(A=\frac{49\frac{1}{20}}{169}\cdot\frac{\frac{4}{5}+\frac{5}{40}}{169}-\frac{19}{37}\)

\(A=\frac{981}{169}\cdot\frac{\frac{32}{40}+\frac{5}{40}}{169}-\frac{19}{37}\)

\(A=\frac{981}{169}\cdot\frac{\frac{37}{40}}{169}-\frac{19}{37}\)

\(A=\frac{981.\frac{37}{40}}{169^2}-\frac{19}{37}\)

\(A=\frac{\frac{36297}{40}}{28561}-\frac{19}{37}\)

\(A=\frac{907,425}{28561}-\frac{19}{37}\)

\(A=\frac{33574,725}{1056757}-\frac{542659}{1056757}\)

\(A=\frac{-509084,275}{1056757}=-0,04604282...\)

Mik chỉ làm đc thế này thôi, ôn thi học kì II tốt nha bạn!

1 tháng 3 2018

trả lời nhanh cái xem nào 

1 tháng 3 2018

ko trả lời thì làm sao giỏi tự giải đi

28 tháng 4 2019

a) \(\frac{2}{3}+\frac{1}{3}\cdot\left(-\frac{2}{5}\right)\\ =\frac{2}{3}+\frac{-2}{15}\\ =\frac{10}{15}+\frac{-2}{15}\\ =\frac{8}{15}\)

b) \(0,75\cdot1\frac{7}{9}-1\frac{2}{5}:\frac{-21}{20}\\ =\frac{3}{4}\cdot\frac{16}{9}-\frac{7}{5}\cdot\frac{-20}{21}\\ =\frac{4}{3}-\frac{-4}{3}\\ =\frac{4}{3}+\frac{4}{3}\\ =\frac{4}{3}\cdot2\\ =\frac{8}{3}\)

c) \(\frac{-2}{17}+\frac{15}{23}+\frac{15}{-17}-\frac{-4}{19}+\frac{8}{23}\\ =\frac{-2}{17}+\frac{15}{23}+\frac{-15}{17}+\frac{4}{19}+\frac{8}{23}\\ =\left(\frac{-2}{17}+\frac{-15}{17}\right)+\left(\frac{15}{23}+\frac{8}{23}\right)+\frac{4}{19}\\ =\left(-1\right)+1+\frac{4}{19}\\ =0+\frac{4}{19}\\ =\frac{4}{19}\)

d) \(2019^0\cdot\left(6-2\frac{4}{5}\right)\cdot3\frac{1}{8}-1\frac{3}{5}:25\%\\ =1\cdot\left(\frac{30}{5}-\frac{14}{5}\right)\cdot\frac{25}{8}-\frac{8}{5}:\frac{1}{4}\\ =1\cdot\frac{16}{5}\cdot\frac{25}{8}-\frac{8}{5}\cdot4\\ =\frac{16}{5}\cdot\frac{25}{8}-\frac{32}{5}\\ =\frac{50}{5}-\frac{32}{5}\\ =\frac{18}{5}\)

e) \(\left(\frac{7}{8}-\frac{1}{2}\right)\cdot2\frac{2}{3}-\frac{3}{7}\cdot\left(2,5^2\right)\\ =\left(\frac{7}{8}-\frac{4}{8}\right)\cdot\frac{8}{3}-\frac{3}{7}\cdot6,25\\ =\frac{3}{8}\cdot\frac{8}{3}-\frac{3}{7}\cdot\frac{25}{4}\\ =1-\frac{75}{28}\\ =\frac{28}{28}-\frac{75}{28}\\ =\frac{-47}{28}\)

19 tháng 6 2019

a, \(\frac{2}{3}+\frac{1}{3}.\left(\frac{-2}{5}\right)\)

= \(\frac{2}{3}+\frac{-2}{15}=\frac{8}{15}\)

b, \(0,75.1\frac{7}{9}-1\frac{2}{5}:\frac{-21}{20}\)

= \(\frac{3}{4}.\frac{16}{9}-\frac{7}{5}.\frac{-20}{21}\)

= \(\frac{4}{3}-\left(\frac{-4}{3}\right)=\frac{8}{3}\)

c, \(\frac{-2}{17}+\frac{15}{23}+\frac{15}{-17}+\frac{4}{19}+\frac{8}{23}\)

= \(\left(\frac{-2}{17}+\frac{-15}{17}\right)+\left(\frac{15}{23}+\frac{8}{23}\right)+\frac{4}{19}\)

= \(\left(-1\right)+1+\frac{4}{19}=0+\frac{4}{19}=\frac{4}{19}\)

d, \(\left(6-2\frac{4}{5}\right).3\frac{1}{8}-1\frac{3}{5}:25\%\)

=> \(\left(6-\frac{14}{5}\right).\frac{25}{8}-\frac{8}{5}:25\%\)

= \(\frac{16}{5}.\frac{25}{8}-\frac{8}{5}.25:100\)

= 10 - 0,4 = 9,6

e, \(\left(\frac{7}{8}-\frac{1}{2}\right).2\frac{2}{3}-\frac{3}{7}.\left(2,5^2\right)\)

=> \(\frac{3}{8}.\frac{8}{3}-\frac{3}{7}.6,25\)

= \(1-\frac{75}{28}=\frac{-47}{28}\)

12 tháng 7 2018

bạn có ghi nhầm đề ko ?