9,25 - 1,14 - 3,1 = 5,01

hok tot

~

\(9,25-1,14-3,1\)

\(=9,25-4,24\)

\(=5,01\)

\(9.25-1.14-3.1\)

\(=8.11-3.1\)

\(=5.01\)

\(3,42+1,36-x=1,25\)

\(\Rightarrow4,78-x=1,25\)

\(\Rightarrow x=4,78-1,25\)

\(\Rightarrow x=3,53\)

3, 42 + 1, 36 - x = 1, 25

=> 4, 78 - x = 1, 25

x = 4, 78 - 1, 25

x = 3, 53

3,42+1,36-x=1,25

<=>4,78-x=1,25

=> x= 4,78-1,25=3,53

812 x 5 + 812 x 7 - 7 - 812 x 2 ???

 toàn câu hỏi sai

=1500

325+6,8+675+3,2=(6,8+3,2)+675+325

                             =10+1000

189 x 125 - 189 x 25

= 189 x ( 125 - 25 )

= 189 x 100

= 18 900

189x125-189x25

=189x(125-25)

=189x100

=18900

TL 

189 x 125 - 189 x 25

= 189 x (125 - 25)

= 189 x 100

= 18900

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 ) 

= 2007 x 2009 + ( 2007 - 1007 ) / 2007 x 2009 + ( 2009 - 1009 )

=2007 x 2009 + 1000 / 2007 x 2009 + 1000

= 1