a,4/5×9/7=36/35

b,3/5:2/7=3/5×7/2=21/10

c,3/7×5/4-5/14=15/28-5/14=5/28

Cảm ơn nha!

\(\dfrac{4}{5}\times\dfrac{3}{7}\times\dfrac{4}{5}\times\dfrac{6}{7}\times\dfrac{4}{14}=\dfrac{4}{5}\times\dfrac{3}{7}+\dfrac{4}{5}\times\dfrac{6}{7}-\dfrac{4}{5}\times\dfrac{2}{7}=\dfrac{4}{5}\times\left(\dfrac{6}{7}+\dfrac{3}{7}-\dfrac{2}{7}\right)=\dfrac{4}{5}\)

a: =4/5-3/8+2/8

=4/5-1/8

=32/40-5/40=27/40

b: =5/9+6/9-1/2

=11/9-1/2

=22/18-9/18=13/18

c: =5/12+9/12+4/12=18/12=3/2

d: =7/28+12/28+22/28=41/28

4/5 x 15/11 x 2/9 = 8/33

4/7 x 2/5 + 4/7 x 3/5 = 4/7

( 5/7 + 7/8 ) x 2 =  89/28

2/14 + 3/7 - 3/14 x 2 = 1/7 

tk mình nhé, mk nhanh nhất

4/5 x 15/11 x2/9

= 4x15x2/5x11x9

= 4x5x3x2/5x11x3x3

= 8/33

địt con mẹ mày lên

\(\dfrac{1}{3}\)-\(\dfrac{2}{15}\)+\(\dfrac{14}{15}\)=\(\dfrac{3}{15}\)-\(\dfrac{2}{15}\)+\(\dfrac{14}{15}\)

=\(\dfrac{13}{15}\)

k tui di

làm rồi

lam giup minh voi

=4/5(3/7+6/7-2/7)=4/5

4/5.(3/7+6/7-4/14)

=4/5.1

=4/5

= 4/5 x ( 3/7 + 6/7 - 4/14 )

= 4/5 x ( 3/7 + 6/7 - 2/7 )

= 4/5 x 7/7

= 4/5

giúp mik đi,mik tick cho,mik cần gấp lắm

\(\dfrac{3}{14}+\dfrac{2}{7}=\dfrac{3}{14}+\dfrac{4}{14}=\dfrac{7}{14}=\dfrac{1}{2}\)

\(\dfrac{6}{5}-\dfrac{1}{4}=\dfrac{24}{20}-\dfrac{5}{20}=\dfrac{24-5}{20}=\dfrac{19}{20}\)

`3/14 +2/7`

`= 3/14 + 4/14`

`= 7/14`

`=1/2`

__

`6/5 -1/4`

`= 24/20 - 5/20`

`= 19/20`