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29 tháng 3 2019

\(a,13\frac{3}{7}+4\frac{5}{13}-8\frac{3}{7}\)

\(=\left(13+4-8\right)+\left(\frac{3}{7}+\frac{5}{13}-\frac{3}{7}\right)\)

\(=9\frac{5}{13}\)

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

\(=3\frac{1}{5}.3\frac{1}{8}-1\frac{3}{5}.4\)

\(=10-6\frac{2}{5}\)

\(=3\frac{3}{5}\)

7 tháng 4 2019

\(A=21\frac{4}{11}-\left(1\frac{3}{5}+7\frac{4}{11}\right)\)

\(A=\frac{235}{11}-\left(\frac{8}{5}+\frac{81}{11}\right)\)

\(A=\left(\frac{235}{11}-\frac{81}{11}\right)+\frac{8}{5}\)

\(A=\frac{154}{11}+\frac{8}{5}\)

\(\Rightarrow A=\frac{78}{5}\)

7 tháng 4 2019

\(B=\left(7\frac{8}{9}+2\frac{3}{13}\right)-\left(4\frac{8}{9}-7\frac{10}{13}\right)\)

\(B=\left(\frac{71}{9}+\frac{29}{13}\right)-\left(\frac{44}{9}-\frac{101}{13}\right)\)

\(B=\left(\frac{71}{9}-\frac{44}{9}\right)+\left(\frac{29}{13}-\frac{101}{13}\right)\)

\(B=\frac{27}{9}+\frac{-72}{13}\)

\(B=3+\frac{-72}{13}\)

\(\Rightarrow B=\frac{-33}{13}\)

P/s: Hoq chắc :v

9 tháng 4 2018

a) 2/7+-3/8+11/7+1/3+1/7+5/-8

=(2/7+11/7+1/7)+(3/8+-5/8)+1/3

=2+2+1/3

=4+1/3

=13/3

b) -3/8+12/25+5/-8+2/-5+13/25

=(-3/8+-5/8)+(12/25+13/25)+-2/5

=-1+1+-2/5

=0+-2/5

=-2/5

c)7/8+1/8*3/8+1/8*5/8

=7/8+1/8*(3/8+5/8)

=7/8+1/8*1

=7/8+1/8

=1

9 tháng 4 2018

a) 2/7+-3/8+11/7+1/3+1/7+5/-8

=(2/7+11/7+1/7)+(3/8+-5/8)+1/3

=2+2+1/3

=4+1/3

=13/3

b) -3/8+12/25+5/-8+2/-5+13/25

=(-3/8+-5/8)+(12/25+13/25)+-2/5

=-1+1+-2/5

=0+-2/5

=-2/5

c)7/8+1/8*3/8+1/8*5/8

=7/8+1/8*(3/8+5/8)

=7/8+1/8*1

=7/8+1/8

=1

Tính :

a) \(\frac{1}{6}.\frac{9}{-8}.\left(-\frac{12}{11}\right)=\frac{1.9.\left(-12\right)}{6.\left(-8\right).11}=\frac{1.3.3}{2.2.11}=\frac{9}{44}\)

b) \(\frac{1}{8}.\frac{-3}{7}+\frac{1}{8}.\frac{-4}{7}\)

\(=\frac{1}{8}.\left(-\frac{3}{7}+\frac{-4}{7}\right)\)

\(=\frac{1}{8}.\frac{-7}{7}=\frac{1}{8}.\left(-1\right)\)

\(=-\frac{1}{8}\)

c) \(\frac{7}{13}.\frac{3}{-5}+\frac{6}{13}.\frac{-3}{5}\)

\(=-\frac{3}{5}.\left(\frac{7}{13}+\frac{6}{13}\right)\)

\(=-\frac{3}{5}.\frac{13}{13}=-\frac{3}{5}.1\)

\(=-\frac{3}{5}\)

5 tháng 8 2019

a, \(\frac{1}{6}.\frac{9}{-8}.\frac{-12}{11}\)

\(\Rightarrow\frac{9}{8}.\frac{2}{11}\)

\(\Rightarrow\frac{9}{4}.\frac{1}{11}\)

\(\Rightarrow\frac{9}{44}\)

b,\(\frac{1}{8}.\frac{-3}{7}+\frac{1}{8}.\frac{-4}{7}\)

\(\Rightarrow\frac{-3}{56}-\frac{1}{2}.\frac{1}{7}\)

\(\Rightarrow\frac{-3}{56}-\frac{1}{2}.\frac{1}{7}\)

\(\Rightarrow\frac{-3}{56}-\frac{1}{14}\)

\(\Rightarrow\frac{-1}{8}\)

c,\(\frac{7}{13}.\frac{3}{-5}+\frac{6}{13}.\frac{-3}{5}\)

\(\Rightarrow\frac{-21}{65}-\frac{18}{65}\)

\(\Rightarrow\frac{-3}{5}\)

8 tháng 2 2019

\(a)\frac{8}{9}x-\frac{2}{3}=\frac{1}{3}x+1\frac{1}{3}\)

\(\Rightarrow\frac{8}{9}x-\frac{1}{3}x=\frac{2}{3}+1\frac{1}{3}\)

\(\Rightarrow\frac{5}{9}x=\frac{2}{3}+\frac{4}{3}\)

\(\Rightarrow\frac{5}{9}x=2\Rightarrow x=2\div\frac{5}{9}=\frac{18}{5}\)

8 tháng 2 2019

\(b)(\frac{-2}{5}+\frac{3}{7})-(\frac{4}{9}+\frac{12}{20}-\frac{13}{25})+\frac{7}{35}\)

\(=\frac{1}{35}-(\frac{4}{9}+\frac{3}{5}-\frac{13}{25})+\frac{1}{5}\)

\(=\frac{1}{35}-(\frac{4}{9}+\frac{15}{25}-\frac{13}{25})+\frac{1}{5}\)

\(=\frac{1}{35}-(\frac{4}{9}+\frac{2}{25})+\frac{1}{5}\)

\(=\frac{1}{35}-\frac{118}{25}+\frac{1}{5}\)

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