\(\frac{9}{16}:\frac{27}{8}=\frac{3^2:3^3}{2^4:2^3}=\frac{\frac{1}{3}}{2}=\frac{1}{6}\)

b tương tự nha

\(\frac{9}{16}:\frac{27}{8}=\frac{9}{16}\cdot\frac{8}{21}=\frac{3\cdot3\cdot4\cdot2}{8\cdot2\cdot7\cdot3}=\frac{14}{3}\)

\(\frac{40}{7}:\frac{5}{14}=\frac{40}{7}\cdot\frac{14}{5}=\frac{4\cdot5\cdot2\cdot7\cdot2}{7\cdot5}=\frac{16}{1}=16\)

Chúc bạn học tốt

Ta có \(\frac{8}{9}+\frac{14}{27}+\frac{1}{9}=\left(\frac{8}{9}+\frac{1}{9}\right)+\frac{14}{27}=1+\frac{14}{27}=\frac{41}{27}\)

Ta có \(\frac{1}{2}+\frac{3}{4}+\frac{1}{2}=\left(\frac{1}{2}+\frac{1}{2}\right)+\frac{3}{4}=1+\frac{3}{4}=\frac{7}{4}\)

\(\frac{8}{9}+\frac{14}{27}+\frac{1}{9}=\left(\frac{8}{9}+\frac{1}{9}\right)+\frac{14}{27}=1+\frac{14}{27}=\frac{41}{27}\)

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

bài 6 \(\frac{2}{2\times4}+\frac{2}{4\times6}+\frac{2}{6\times8}+\ldots+\frac{2}{80\times82}+\frac{2}{82\times84}\)

= \(\frac12-\frac14+\frac14-\frac16+\frac16-\cdots+\frac{1}{80}-\frac{1}{82}+\frac{1}{82}-\frac{1}{84}\)

= \(\frac12-\left(\frac14-\frac14\right)-\left(\frac16-\frac16\right)-\cdots-\left(\frac{1}{82}-\frac{1}{82}\right)-\frac{1}{84}\)

=\(\frac12-0-0-\frac{1}{84}\)

=\(\frac12\) - \(\frac{1}{84}\)

=\(\frac{42}{84}-\frac{1}{84}\)

=\(\frac{41}{84}\)

Bài 7

a)\(\frac{19}{4}=4\frac34\)

b)\(\frac{27}{5}=5\frac25\)

c)\(\frac{56}{8}=7\frac08\)

\(\frac{3}{2}+\frac{3}{8}+\frac{3}{32}+\frac{3}{128}+\frac{3}{512}\)

=\(\frac{3}{1.2}+\frac{3}{2.4}+\frac{3}{4.8}+\frac{3}{8.16}+\frac{3}{16.32}\)

=\(\frac{3}{1}-\frac{3}{2}+\frac{3}{2}-\frac{3}{4}+\frac{3}{4}-\frac{3}{8}+\frac{3}{8}-\frac{3}{16}+\frac{3}{16}-\frac{3}{36}\)

=\(\frac{3}{1}-\frac{3}{36}\)=\(\frac{35}{12}\)

a)=768/512+192/512+48/512+12/512+3/512

=768+192+48+12+3/512

=1023/512 

b)=405/81+135/81+45/81+15/81+5/81

=405+135+45+15+5/81

=595/81

c)=256/192+64/192+16/192+4/192+1/192

=256+64+16+4+1/192

=341/192

c.                                  1/6+7/2=11/3

                                                                                           Chúc bạn học tốt nếu đúng thì giúp mình nhé.          

                            8/9:6/27-3=4-3=1    

Bài làm :

\(c,\frac{1}{6}+\frac{5}{2}\times\frac{7}{5}\)

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

\(=\frac{11}{3}\)

\(\frac{8}{9}:\frac{6}{27}-3\)

\(=\frac{8}{9}\times\frac{9}{2}-3\)

\(=4-3\)

\(=1\)

Học tốt

\(\frac{4}{27}\cdot\frac{9}{2}+\frac{7}{15}=\frac{2}{3}+\frac{7}{15}=\frac{17}{15}\)

( \(\cdot\)là dấu nhân đó)

=2/3+7/15

=10/15+7/15

=17/15

 Đặt   \(A=\frac{1}{3}+\frac{1}{9}+.......+\frac{1}{59049}\)

  \(3A=3.\left(\frac{1}{3}+\frac{1}{9}+......+\frac{1}{59049}\right)\)

\(3A=1+\frac{1}{3}+........+\frac{1}{19683}\)

\(3A-A=\left(1+\frac{1}{3}+......+\frac{1}{19683}\right)-\left(\frac{1}{3}+\frac{1}{9}+........+\frac{1}{59049}\right)\)

\(2A=1-\frac{1}{59049}\)

\(2A=\frac{59048}{59049}\)

\(A=\frac{59048}{59049}:2\)

\(A=\frac{59048}{118098}\)