=3/5*\((\)2/7+4/7\()\)+2/5

=3/5*6/7+2/5

=18/35+2/5

=32/35

`2/5 xx 4/7 + 3/5 xx 4/7`

`= 4/7 xx (2/5 + 3/5)`

`= 4/7 xx 1`

`= 4/7`

\(\dfrac{2}{5}\times\dfrac{4}{7}+\dfrac{3}{5}\times\dfrac{4}{7}=\left(\dfrac{2}{5}+\dfrac{3}{5}\right)\times\dfrac{4}{7}=\dfrac{5}{5}\times\dfrac{4}{7}=1\times\dfrac{4}{7}=\dfrac{4}{7}\)

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

7/11 : 3/5 + 4/11 : 3/5

= (7/11 + 4/11) : 3/5

=1:3/5=5/3

\(\left(\dfrac{7}{11}+\dfrac{4}{11}\right):\dfrac{3}{5}=\dfrac{11}{11}:\dfrac{3}{5}=\dfrac{1}{1}:\dfrac{3}{5}=\dfrac{1}{1}\times\dfrac{5}{3}=\dfrac{5}{3}\)

= (7/11 + 4/11) : 3/5

=1:3/5=5/3

=(3/7+4/7)+(4/9+5/9)

=1+1=2

\(\dfrac{3}{7}+\dfrac{4}{9}+\dfrac{4}{7}+\dfrac{5}{9}=\left(\dfrac{3}{7}+\dfrac{4}{7}\right)+\left(\dfrac{4}{9}+\dfrac{5}{9}\right)=\dfrac{7}{7}+\dfrac{9}{9}=1+1=2\)

=(3/7+4/7)+(5/9+4/9)=1+1=2

Tk mình đi mọi người mình bị âm nè!

ai tk mình mình tk lại cho!!!

4/5 * ( 3/7 + 4/5 - 4/14 )

rồi bạn tính tiếp đi nhé !

Nếu không thính thì bạn ni đổi đi nhé !

4/5* (3/7+6/7-4/14) = 4/5 * (9/7 - 4/14) = 4/5 *(18/14 -4/14) = 4/5 * 1= 4/5

\(\dfrac{4}{7}x\left(\dfrac{2}{5}+\dfrac{3}{5}\right)=\dfrac{4}{7}x1=\dfrac{4}{7}\)

2/5 x 4/7 + 3/5 x 4/7

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

= 1 x 4/7

= 4/7

    2/5 *4/7+3/5*4/7

=( 2/5 + 3/5 ) *4/7 

= 1 * 4/7

= 4/7

`4/5 xx 3/7 + 4/5 xx 6/7 - 4/5 xx 4/14`

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

`= 4/5 xx 1`

`= 4/5`

A) 5/4 x X = 3/8 + 5/12

5/4 x X = 19/24

        X  = 19/24 : 5/4

        X  = 19/30

vậy x =...

B, 3 x 7/10 + 7/10 x 5 + 2 x 7/10

  = 7/10 x ( 3 + 5 + 2)

  = 7/10 x 10

  = 7

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