812x5+812x7-812x2

=812x(5+7-2)

=812x10

=8120

   812 x 5 + 812 x 7 - 812 x 2

= 812 x ( 5 + 7 - 2 )

= 812 x  10

= 8120

Chúc bn hok tốt !

   812 x 5 + 812 x 7 - 812 x 2
= 812 x ( 5 + 7 - 2 )
= 812 x  10
= 8120

819 x 16 - 819 x 5 - 819

= 819 x 16 - 819 x 5 - 819 x 1

= 819 x ( 16 - 5 - 1 )

= 819 x 10

= 819

a )     \(\frac{5}{11}\times\frac{7}{25}\times\frac{15}{11}\times\frac{1}{5}\)

\(=\frac{5\times7\times15\times1}{11\times25\times11\times5}\)

\(=\frac{1\times7\times3\times1}{11\times5\times11\times1}\)

\(=\frac{21}{\left(10\times5+5\times1\right)\times11}\)

\(=\frac{21}{55\times11}\)

\(=\frac{21}{55\times10+55}\)

\(=\frac{21}{550+55}\)

\(=\frac{21}{605}\)   ( quá đơn giản ) 

\(\)

A) \(\frac{5}{11}\times\frac{7}{25}-\frac{15}{11}\times\frac{1}{5}\)

\(=\frac{5\times7}{11\times25}-\frac{15\times1}{11\times5}\)

\(=\frac{35}{10\times25+25}-\frac{15}{55}\)

\(=\frac{35}{250+25}-\frac{15}{55}\)

\(=\frac{35}{275}-\frac{15}{55}\)

\(=\frac{7}{55}-\frac{15}{55}\)

\(=\frac{7-15}{55}\)

\(=\frac{-8}{55}\)

bài ở dưới mới đúng nhà ( bài không có chữ đơn giản quá ) 

     13,25\(\times\)4 + 13,25 \(\times\)5 + 13,25 \(\times\)2 - 13,25

= 13,25 \(\times\)( 4+5+2-1)

= 13,25 \(\times\)10

= 132,5

tym cho mk nhé

\(\frac{1}{3}x\)\(\frac{1}{2}-\frac{1}{5}x\)\(\frac{1}{2}\)

=(\(\frac{1}{3}-\frac{1}{5}\)) x \(\frac{1}{2}\)

=\(\frac{2}{15}x\)\(\frac{1}{2}\)

=\(\frac{1}{15}\)

1/3 * 1/2 - 1/5 * 1/2

= (1/3 + 1/5) * 1/2

=8/15*1/2

=4/15

1\3x1\2-1\5x1\2=1\3 x1\2-1\5x1\2=1\7-1\6=1\1=1

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

Giúp tớ với mọi người ơi

`a) 5 / 13 xx 4 / 15 xx 13 = [ 5 xx 4 xx 13 ] / [ 13 xx 5 xx 3 ] = 4 / 3`

`b) ( 3 / 7 + 5 / 2 ) xx 7 / 5 = 3 / 7 xx 7 / 5 + 5 / 2 xx 7 / 5 = 3 / 5 + 7 / 2 = 6 / 10 + 35 / 10 = 41 / 10`

`c) 1 / 5 xx 11 / 18 + 11 / 18 xx 3 / 5 = 11 / 18 xx ( 1 / 5 + 3 / 5 ) = 11 / 18 xx 4 / 5 = [ 11 xx 2 xx 2 ] / [ 2 xx 9 xx 5 ] = 22 / 45`

\(a,\dfrac{5}{13}\times\dfrac{4}{15}\times13=\dfrac{4}{3}\)

\(b,\left(\dfrac{3}{7}+\dfrac{5}{2}\right)\times\dfrac{7}{5}=\left(\dfrac{6}{14}+\dfrac{35}{14}\right)\times\dfrac{7}{5}=\dfrac{41}{14}\times\dfrac{7}{15}=\dfrac{41}{30}\)

\(c,\dfrac{1}{5}\times\dfrac{11}{18}+\dfrac{11}{18}\times\dfrac{3}{5}=\dfrac{11}{18}\times\left(\dfrac{1}{5}+\dfrac{3}{5}\right)=\dfrac{11}{18}\times\dfrac{4}{5}=\dfrac{22}{45}\)

2014 + 2014 x 2 + 7 x 2014

= 2014 x (1 + 2 + 7)

= 2017 x 10

= 20170

2014 + 2014 x 2 + 7 x 2014

= 2014 + 2014 x 2 + 7 + 2014 +1

= 2014 x ( 7 + 2 + 1 )

= 2014 x 10

= 20140

2014 + 2014 x 2 + 2014 x 7

=2014 x (1 + 2 + 7)

=2014 x 10

=20140

476 x (34267 - 28765 )

=476 x 5502

=2618952

kb nhé