7/19x1/2+7/19x2/3

=7/19(1/2+2/3)

=7/19x7/6

=49/114

a)3/5x5/3x8/27=1x8/27=8/27

b)7/19x(1/3+2/3)=7/19x1=7/19

\(\frac{3}{5}x\frac{8}{27}x\frac{5}{3}=\frac{3}{3}x\frac{5}{5}x\frac{8}{27}=\frac{8}{27}\)

\(\frac{7}{19}x\frac{1}{3}+\frac{7}{19}x\frac{2}{3}=\frac{7}{19}x\left(\frac{1}{3}+\frac{2}{3}\right)=\frac{7}{19}\)

A)3/5x8/27x5/3

=8/27x(3/5x5/3)

=8/27x1

=8/27

B)7/19x1/3+7/19x2/3

=7/19x(1/3+2/3)

=7/19x1

=7/19

sai thì thông cảm cho cho mk nhé, có hứng thì kb luôn

a)2

b)75/37

c)0

d)8/27

e)7/19

f)4

ok

a) \(\frac{2}{9}+\frac{1}{5}+\frac{7}{9}+\frac{4}{5}=\left(\frac{2}{9}+\frac{7}{9}\right)+\left(\frac{1}{5}+\frac{4}{5}\right)= 1+1=2 \)

b) \(\frac{19}{37}+\left(1+\frac{19}{37}\right)=\left(\frac{19}{37}-\frac{19}{37}\right)+1=0+1=1\)

c) \(\frac{9}{8}-\left(\frac{17}{7}-\frac{3}{7}\right)+\frac{7}{8}=\frac{9}{8}+\frac{7}{8}-\left(\frac{17}{7}-\frac{3}{7}\right)=2-2=0\)

d) \(\frac{3}{5}\times\frac{8}{27}\times\frac{5}{3}=\frac{3}{5}\times\frac{5}{3}\times\frac{8}{27}=1\times\frac{8}{27}=\frac{8}{27}\)

e) \(\frac{7}{19}\times\frac{1}{3}+\frac{7}{19}\times\frac{2}{3}=\frac{7}{19}\times\left(\frac{1}{3}+\frac{2}{3}\right)=\frac{7}{19}\times1=\frac{7}{19}\)

f) \(\frac{12}{5}\times4-4\times\frac{7}{5}=4\times\left(\frac{12}{5}-\frac{7}{5}\right)=4\times1=4\)

   5 x 7 + 5 x 3 + 5 x 4 

= 5 x ( 7 + 3 + 4 ) 

= 5 x 14 

= 70 

5x7+5x3+5x4

=5x(7+3)+20

=5x10+20

=50+20

=70.

5 . 7 + 5 . 3 + 5 . 4

= 5( 7 + 3 + 4 )

= 5 . 14

= 70 

a, \(=\left(\dfrac{4}{7}+\dfrac{3}{7}\right)+\left(\dfrac{3}{5}+\dfrac{3}{5}\right)=1+\dfrac{6}{5}=\dfrac{5+6}{5}=\dfrac{11}{5}\)

\(=\left(\dfrac{3}{7}+\dfrac{8}{14}\right)+\left(\dfrac{3}{10}+\dfrac{7}{10}\right)=1+1=2\)

Mtbrvrvsdqdqd

= 7/5×(5/3 - 1/3 + 2/3 - 3/3)

= 7/5 × 1

= 7/5

\(\dfrac{7}{19}\times\dfrac{1}{3}+\dfrac{7}{13}\times\dfrac{2}{3}\)

\(=\dfrac{7}{19}\times\left(\dfrac{1}{3}+\dfrac{2}{3}\right)\)

\(=\dfrac{7}{19}\times1\)

\(=\dfrac{7}{19}\)

\(=\dfrac{2}{5}\cdot\dfrac{7}{3}\cdot\dfrac{3}{7}\cdot\dfrac{5}{2}+2020=1+2020=2021\)