\(\dfrac{7}{9}=\dfrac{7\times5}{9\times5}=\dfrac{35}{45}\)
\(\dfrac{2}{5}=\dfrac{2\times9}{5\times9}=\dfrac{18}{45}\)
\(---------\)
\(\dfrac{6}{7}=\dfrac{6\times3}{7\times3}=\dfrac{18}{21}\)
\(\dfrac{17}{21}=\dfrac{17}{21}\)

\(\dfrac{39}{75}=\dfrac{39:3}{75:3}=\dfrac{13}{25}\)

Rút gọn cho 3 

=13/25 

xin hay nhất ><

\(\dfrac{54}{72}=\dfrac{3}{4}\)
\(\dfrac{92}{100}=\dfrac{23}{25}\)
\(\dfrac{126}{165}=\dfrac{42}{55}\)
\(\dfrac{1717}{1515}=\dfrac{17}{15}\)

54 phần 72=`54/72=3/4`

92 phần 100=`92/100=23/25`

126 phần 165=`126/165=42/55`

1717 phần 1515=`1717/1515=17/15`

\(\dfrac{5}{7};\dfrac{28}{7}\)

\(\dfrac{5}{6}=\dfrac{5\times5}{6\times5}=\dfrac{25}{30}\)

25/30 nhé

\(\dfrac{3.4.7}{3.4.8.9}=\dfrac{7}{72}\)

\(\dfrac{3\times4\times7}{12\times8\times9}\)
\(=\dfrac{12\times7}{12\times8\times9}\)
\(=\dfrac{7}{72}\)

`(4xx5xx6)/(12xx8xx10)=(4xx5xx6)/(6xx2xx4xx2xx5xx2)= 1/(2xx2xx2)=1/8`

120/960 nhé

5x6x7x9=1890

12x7x27=2268

a,5x6x7x9=1890

b,12x7x27=2268

like cho mình nha :<

a.\(\dfrac{17}{60}=\dfrac{17}{60}\)
\(\dfrac{4}{5}=\dfrac{4\times12}{5\times12}=\dfrac{48}{60}\)
b.\(\dfrac{5}{6}=\dfrac{5\times4}{6\times4}=\dfrac{20}{24}\)
\(\dfrac{9}{8}=\dfrac{9\times3}{8\times3}=\dfrac{27}{24}\)
c.\(\dfrac{1}{2}=\dfrac{1\times6}{2\times6}=\dfrac{6}{12}\)
\(\dfrac{2}{3}=\dfrac{2\times4}{3\times4}=\dfrac{8}{12}\)
\(\dfrac{3}{4}=\dfrac{3\times3}{4\times3}=\dfrac{9}{12}\)
d.\(\dfrac{1}{2}=\dfrac{1\times6}{2\times6}=\dfrac{6}{12}\)
\(\dfrac{2}{3}=\dfrac{2\times4}{3\times4}=\dfrac{8}{12}\)
\(\dfrac{7}{12}=\dfrac{7}{12}\)

2016/1186=1008/593

594/1284=99/214

4684/4286=2342/2143

7976/9970=4/5