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24 tháng 4 2018

a) \(\left(2\frac{5}{6}+1\frac{4}{9}\right):\left(10\frac{1}{12}-9\frac{1}{2}\right)\)

\(=\left(\frac{17}{6}+\frac{13}{9}\right):\left(\frac{121}{12}-\frac{19}{2}\right)\)

\(=\frac{77}{18}:\frac{7}{12}\)

\(=\frac{22}{3}\)

b) \(1\frac{5}{18}-\frac{5}{18}.\left(\frac{1}{15}+1\frac{1}{12}\right)\)

\(=\frac{23}{18}-\frac{5}{18}.\left(\frac{1}{15}+\frac{13}{12}\right)\)

\(=\frac{23}{18}-\frac{5}{18}.\frac{23}{20}\)

\(=\frac{23}{18}-\frac{23}{72}\)

\(=\frac{23}{24}\)

c) \(-1\frac{1}{7}.\left(9\frac{1}{2}-8,75\right):\frac{2}{7}+0,625:1\frac{2}{3}\)

\(=\frac{-8}{7}.\left(\frac{19}{2}-\frac{35}{4}\right):\frac{2}{7}+\frac{5}{8}:\frac{5}{3}\)

\(=\frac{-8}{7}.\frac{3}{4}:\frac{2}{7}+\frac{3}{8}\)

\(=\frac{-8}{7}.\frac{3}{4}.\frac{7}{2}+\frac{3}{8}\)

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

\(=\frac{-21}{8}\)

Chúc bn học tốt !!

27 tháng 5 2019

\(\left(\frac{-2}{3}+\frac{3}{7}\right):\frac{4}{5}+\left(\frac{-1}{3}+\frac{4}{7}\right):\frac{4}{5}\)

\(=\left(\frac{-2}{3}+\frac{3}{7}+\frac{-1}{3}+\frac{4}{7}\right):\frac{4}{5}\)

\(=\left[\left(\frac{-2}{3}+\frac{-1}{3}\right)+\left(\frac{3}{7}+\frac{4}{7}\right)\right]:\frac{4}{5}\)

\(=\left[\left(-1+1\right)\right]:\frac{4}{5}\)

\(=0:\frac{4}{5}=0\)

~ Hok tốt ~

27 tháng 5 2019

cau A= o nha ban con cau B minh ko chac vi so minh ra hoi lon 1 ti

25 tháng 4 2018

= [ 60/90 - ( 12/15 + 10/15) ] : 6/5

= ( 2/3 - 22/15 ) x 5/6

= ( 10/15 - 22/15 ) x 5/6

= -12/15 x 5/6

= -60/90

= -2/3

25 tháng 4 2018

( 15/10 x 4/9 - ( 4/5 + 2/3 )) : 6/5

( 15/10 x 4/9 - ( 12/15 + 10/15 )) : 6/5

(30/45 - 66/45 ) : 6/5

-12/15 : 6/5 ( đã rút gọn -36/45 = -12/15 )

-2/3

k mk na <3

HQ
Hà Quang Minh
Giáo viên
8 tháng 10 2023

a) Cách 1:

 \(\begin{array}{l}\left( {\frac{{ - 2}}{{ - 5}} + \frac{{ - 5}}{{ - 6}}} \right) + \frac{4}{5} = \frac{2}{5} + \frac{5}{6} + \frac{4}{5}\\ = \frac{{12}}{{30}} + \frac{{25}}{{30}} + \frac{{24}}{{30}} = \frac{{61}}{{30}}\end{array}\)

Cách 2:

\(\begin{array}{l}\left( {\frac{{ - 2}}{{ - 5}} + \frac{{ - 5}}{{ - 6}}} \right) + \frac{4}{5} = \left( {\frac{2}{5} + \frac{4}{5}} \right) + \frac{5}{6}\\ = \frac{6}{5} + \frac{5}{6} = \frac{{36}}{{30}} + \frac{{25}}{{30}} = \frac{{61}}{{30}}\end{array}\)

b) Cách 1:

 \(\begin{array}{l}\frac{{ - 3}}{{ - 4}} + \left( {\frac{{11}}{{ - 15}} + \frac{{ - 1}}{2}} \right) = \frac{3}{4} + \frac{{ - 11}}{{15}} + \frac{{ - 1}}{2}\\ = \frac{{45}}{{60}} + \frac{{ - 44}}{{60}} + \frac{{ - 30}}{{60}}\\ = \frac{{ - 29}}{{60}}\end{array}\).

Cách 2:

\(\begin{array}{l}\frac{{ - 3}}{{ - 4}} + \left( {\frac{{11}}{{ - 15}} + \frac{{ - 1}}{2}} \right) = \frac{3}{4} + \frac{{ - 11}}{{15}} + \frac{{ - 1}}{2}\\ = \left( {\frac{3}{4} + \frac{{ - 1}}{2}} \right) + \frac{{ - 11}}{{15}}\\ = \left( {\frac{3}{4} + \frac{{ - 2}}{4}} \right) + \frac{{ - 11}}{{15}}\\ = \frac{1}{4} + \frac{{ - 11}}{{15}}\\ = \frac{{15}}{{60}} + \frac{{ - 44}}{{60}}\\ = \frac{{ - 29}}{{60}}\end{array}\)