Ta có : 

\(\frac{\frac{2}{5}-\frac{2}{9}+\frac{2}{11}}{\frac{7}{5}-\frac{7}{9}+\frac{7}{11}}:\frac{\frac{1}{3}-\frac{1}{4}+\frac{1}{5}}{\frac{7}{6}-\frac{7}{8}+\frac{7}{10}}\)

\(=\)\(\frac{2\left(\frac{1}{5}-\frac{1}{9}+\frac{1}{11}\right)}{7\left(\frac{1}{5}-\frac{1}{9}+\frac{1}{11}\right)}:\frac{\frac{1}{3}-\frac{1}{4}+\frac{1}{5}}{\frac{7}{2}\left(\frac{1}{3}-\frac{1}{4}+\frac{1}{5}\right)}\)

\(=\)\(\frac{2}{7}:\frac{2}{7}\)

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

\(=\)\(1\)

Chúc bạn học tốt ~ 

\(=\frac{2-2+2}{7-7+7}:\frac{\frac{2}{6}-\frac{2}{8}+\frac{2}{10}}{\frac{7}{6}-\frac{7}{8}+\frac{7}{10}}\)

\(=\frac{2}{7}:\frac{2-2+2}{7-7+7}\)

\(=\frac{2}{7}:\frac{2}{7}\)

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

\(=\frac{2.7}{7.2}\)

\(=\frac{1.1}{1.1}\)

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

\(=1\)

a) 20,7 + 1,47 : 7 - 0,23 . 5

= 20,7 + 0,21 – 1,15

= 20,91 – 1,15

= 19,76

Ở trên vietjack có đó bn =)

a, 20,7 + 1,47 : 7 - 0,23 . 5

=\(\frac{207}{10}+\frac{147}{100}:7-\frac{23}{100}.5\)

= \(\frac{207}{10}+\frac{21}{100}-\frac{23}{20}\)

= \(\frac{2091}{100}+\frac{-23}{20}\)

= \(\frac{494}{25}\)

\(a,20,7+1,47:7-0,23\cdot5\)

\(=20,7+0,21-1,15=19,76\)

\(b,1\frac{4}{5}\cdot\frac{7}{8}+\frac{4}{29}:\frac{5}{58}-1\frac{3}{10}\)

\(=\frac{9}{5}\cdot\frac{7}{8}+\frac{4}{29}:\frac{5}{58}-\frac{13}{10}\)

\(=\frac{9\cdot7}{5\cdot8}+\frac{4}{29}\cdot\frac{58}{5}-\frac{13}{10}\)

\(=\frac{63}{40}+\frac{4}{1}\cdot\frac{2}{5}-\frac{13}{10}\)

\(=\frac{63}{40}+\frac{8}{5}-\frac{13}{10}=\frac{63}{40}+\frac{64}{40}-\frac{52}{40}=\frac{63+64-52}{40}=\frac{75}{40}=\frac{15}{8}\)

a/ 545/273

b/ 5/11

c/ -1

1 nha bn

bằng 1 nha bạn

 k tui nha

thanks

P/s : Đúng nha 

Ta có : 

\(\frac{\frac{2}{5}-\frac{2}{9}+\frac{2}{11}}{\frac{7}{5}-\frac{7}{9}+\frac{7}{11}}:\frac{\frac{1}{3}-\frac{1}{4}+\frac{1}{5}}{\frac{7}{6}-\frac{7}{8}+\frac{7}{10}}\)

\(=\frac{2\left(\frac{1}{5}-\frac{1}{9}+\frac{1}{11}\right)}{7\left(\frac{1}{5}-\frac{1}{9}+\frac{1}{11}\right)}:\frac{2\left(\frac{1}{6}-\frac{1}{8}+\frac{1}{10}\right)}{7\left(\frac{1}{6}-\frac{1}{8}+\frac{1}{10}\right)}\)

\(=\frac{2}{7}:\frac{2}{7}\)

\(=1\)

~ Ủng hộ nhé 

\(5\frac{2}{7}\).\(\frac{8}{11}+5\frac{2}{7}\).\(\frac{5}{11}-5\frac{2}{7}\).\(\frac{2}{11}\)

=\(5\frac{2}{7}\).\(\)(\(\frac{8}{11}+\frac{5}{11}-\frac{2}{11}\))

=\(5\frac{2}{7}\).1

=\(5\frac{2}{7}\)

\(1\)) \(\frac{7}{19}.\frac{8}{11}+\frac{7}{19}.\frac{3}{11}+\frac{12}{19}\)

\(=\frac{7}{19}\left(\frac{8}{11}+\frac{3}{11}\right)+\frac{12}{19}\)

\(=\frac{7}{19}+\frac{12}{19}\)

\(=1\)

\(2\)) \(\frac{\frac{2}{5}+\frac{2}{7}-\frac{2}{9}-\frac{2}{11}}{\frac{4}{5}+\frac{4}{7}-\frac{4}{9}-\frac{4}{11}}\)

\(=\frac{\frac{2}{5}+\frac{2}{7}-\frac{2}{9}-\frac{2}{11}}{2\left(\frac{2}{5}+\frac{2}{7}-\frac{2}{9}-\frac{2}{11}\right)}\)

\(=\frac{1}{2}\)

1. \(\frac{7}{19}\times\frac{8}{11}+\frac{7}{19}\times\frac{3}{11}+\frac{12}{19}\)

\(=\frac{7}{19}\left(\frac{8}{11}+\frac{3}{11}\right)+\frac{12}{19}\)

\(=\frac{7}{19}\times1+\frac{12}{19}=\frac{19}{19}=1\)

2. \(\frac{\frac{2}{5}+\frac{2}{7}-\frac{2}{9}-\frac{2}{11}}{\frac{4}{5}+\frac{4}{7}-\frac{4}{9}-\frac{4}{11}}\)

\(=\frac{\frac{2}{5}+\frac{2}{7}-\frac{2}{9}-\frac{2}{11}}{2\left(\frac{2}{5}+\frac{2}{7}-\frac{2}{9}-\frac{2}{11}\right)}=\frac{1}{2}\)

giup minh voi

\(\frac{\frac{2}{5}-\frac{2}{9}+\frac{2}{11}}{\frac{7}{5}-\frac{7}{9}+\frac{7}{11}}:\frac{\frac{1}{3}-\frac{1}{4}+\frac{1}{5}}{\frac{7}{6}-\frac{7}{8}+\frac{7}{10}}\)

\(=\frac{2\left(\frac{1}{5}-\frac{1}{9}+\frac{1}{11}\right)}{7\left(\frac{1}{5}-\frac{1}{9}+\frac{1}{11}\right)}:\frac{\frac{1}{3}-\frac{1}{4}+\frac{1}{5}}{\frac{7}{2}\left(\frac{1}{3}-\frac{1}{4}+\frac{1}{5}\right)}\)

\(=\frac{2}{7}:\frac{1}{\frac{7}{2}}=\frac{2}{7}:\frac{2}{7}=1\)

\(\frac{5}{7}\).\(\frac{5}{11}\)+\(\frac{5}{7}\).\(\frac{8}{11}\)-\(\frac{5}{7}\).\(\frac{2}{11}\)

=\(\frac{5}{7}\)(\(\frac{5}{11}\)+\(\frac{8}{11}\)-\(\frac{2}{11}\))

=\(\frac{5}{7}\).1

=\(\frac{5}{7}\)